thu gọn và sắp xếp luỹ thừa của biến
f(x)= 2x^2 -x +3 -4x -x^4
g(X)= 4X^2 + 2X + X^4 -2 + 3X

Note that the expected value of the retailers profit is - $114. This means he made a loss.

To find the expected value we must proceed as follows

Expected Value - E(F) is

Probability of F - P(F)

= 100 x ($100 - $200) + (P(F) = $50) x ($50 - $200) + (P(F) = $ -200) x ( $ - 200 - $200) +  (P(F)   = $- 350) x ($ -350  $ 200)

= (0.9) x (-100) + (0.07 ) x (-150) + (0.01)  x  (-550)  + (0.02) x (-400)

= - 90  - 10.5  - 5.5 -8

E(F) = $ -114

So it is right to state that the expected value of the retailer's profit per protection plan sold is -$114, which  is a loss.

Learn more about expected value:
https://brainly.com/question/29574962
#SPJ4

Full Question:

An electronics retailer sells mobile phones with an optional protection plan for $100. In case of an accident, the customer pays a $50 deductible and the retailer covers the rest of the repair cost, which is typically $200 per repair. The protection plan covers a maximum of 333 repairs.

Let X be the number of repairs a randomly chosen customer uses under the protection plan, and let F be the retailer's profit from one of these protection plans. The probability distributions of X and F are:

X = number of repairs: 0 1 2 3

Probability: 0.90 0.07 0.02 0.01

F = retailer profit: $100-$50-$200-$350

Probability: 0.90 0.07 0.02 0.01

The task is to find the expected value of the retailer's profit per protection plan sold.

The statement that explains the negative and nonlinear relationship between group size and percent woodland is given by the percent of woodland increases, the number of deer observed in a group decreases quickly at first and then more slowly.

This statement suggests that as the amount of woodland id increases, when the number of deer in a group decreases.

However, the rate of decrease is not constant, but rather decreases more slowly as the percent of woodland increases.

This suggests that there may be some threshold or tipping point.

At which the relationship between group size and percent woodland becomes less pronounced.

This kind of relationship is not uncommon in ecological studies.

Where factors like habitat availability, food availability, and predation risk can all influence animal behavior and population dynamics.

Nonlinear relationships like this one can help researchers better understand complex interplay between these factors and behavior of animals they study.

Learn more about percent here

brainly.com/question/24902797

#SPJ4

The sum of the series under the interval (3, 6) will be negative 4.

Given that:

Series, ∑ (2k - 10)

A series is a sum of sequence terms. That is, it is a list of numbers with adding operations between them.

The sum of the series under the interval (3, 6) is calculated as,

∑₃⁶ (2k - 10) = (2 x 3 - 10) + (2 x 4 - 10) + (2 x 5 - 10) + (2 x 6 - 10)

∑₃⁶ (2k - 10) = - 4 - 2 + 0 + 2

∑₃⁶ (2k - 10) = -4

More about the series link is given below.

https://brainly.com/question/10813422

#SPJ1

The derivative of the function f(x) = (x³ - 5x)(2x-1) after simplification is 6x⁴ - 10x³ - 10x².

We apply the product rule and simplify to determine the derivative of,

f(x) = (x³ - 5x)(2x-1).

The product rule is used to determine the derivative of the given function f(x),

h(x) = a.b, then after applying product rule,

h'(x) = (a)(d/dx)(b) + (b)(d/dx)(a).

Applying this for function f,

f'(x) = 6x⁴ - 25x² - 10x³ + 15x²

f'(x) = 6x⁴ - 10x³ - 10x².

Therefore, f'(x) = 6x⁴ - 10x³ - 10x² is the derivative of f(x) after simplifying the function.

To know more about derivative, visit,

https://brainly.com/question/23819325

#SPJ4

Answer:

unfortunately there's no questions to be answered

Answer is original amount paid to the transportation company was $800.

Let's work backwards from the final amount of $400 to find the original amount paid to the transportation company.

First, we know that percentage given is 80% of what was left after wages went towards supplies. So, if $400 was left after wages were paid, then:

0.8(400) = $320 went towards supplies.

Next, we know that 60% of the original amount went towards wages. So, if $320 went towards supplies, then the remaining amount that went towards wages was:

0.4(original amount) = $320

Solving for the original amount:

Original amount = $320 / 0.4 = $800

Therefore, the original amount paid to the transportation company was $800.

To know more about percentages:

https://brainly.com/question/843074

#SPJ11

The equation for revenue R in terms of the number of rides x is given by R = px, where p is the amount charged per ride (in dollars).

The equation for the revenue R in terms of the number of rides can be derived by multiplying the number of rides with the amount charged per ride.

Let the amount charged per ride be p (in dollars).

Then, the equation for revenue R can be written as R = px.

Note that the amount charged per ride is not given in the problem. It can be assumed that the amount charged is a fixed amount for all the rides.

However, the equation for revenue can still be written in terms of the variable p as R = px.

To know more about revenue, refer here:

https://brainly.com/question/29148322#

#SPJ11

The expression represents the second partial sum for 2(0. 4) + 2(0. 4)2 2(0. 4)2 + 2(0. 4)3 2 + 2(0. 4) 0 + 2(0. 4)1 is 0.8.

The second partial sum of a sequence refers to the sum of the first two terms of the sequence.

The given sequence is: 2(0.4) + 2(0.4)^2 + 2(0.4)^2 + 2(0.4)^3 + 2(0.4)^0 + 2(0.4)^1

To find the second partial sum, we simply add the first two terms of the sequence:

2(0.4) + 2(0.4)^2 = 0.8

Therefore, the expression that represents the second partial sum for the given sequence 2(0. 4) + 2(0. 4)2 2(0. 4)2 + 2(0. 4)3 2 + 2(0. 4) 0 + 2(0. 4)1 is 0.8.

To learn more about  partial sum : https://brainly.com/question/28173651

#SPJ11

Answer:

if the diagonal is 10 then the sides are 3*2 and 4*2 which is 6 and 8 respectively because the diagonal makes it a right angled triangle whereby the the 3,4,5 line steps in, so if the diagonal(hypotenuse) is 10 the 10/5 is 2 then you multiply both 3 and 4 by 2 and that gives you the length of two sides

Answer:

1 hour to build a website

5 hours to update websites

Step-by-step explanation:

x is the hours to build a website

y is the hours to update websites

x + y = 6 ------> 25x + 25y = 150

25x + 15y = 100

10y = 50

y = 5

25x + 15 (5) = 100

25x + 75 = 100

25x = 25

x = 1

So, LaShawn needs 1 hour to build a website and 5 hours to update websites to allow him to reach his goals.

a) The probability that, for at least 15 packs, the average weight of the erasers in the pack is at least 31.95 g is approximately 0.0384.

b) The probability that, on average, the unit finds at least 37.2 "good" erasers per day is approximately 0.3133.

a) To solve this problem, we need to use the central limit theorem. According to this theorem, the distribution of sample means becomes approximately normal, regardless of the shape of the population distribution, when the sample size is sufficiently large (usually, n >= 30). In this case, since the sample size is 45, we can assume that the distribution of sample means will be approximately normal.

Now, we need to find the probability that the average weight of at least 15 packs is at least 31.95 g. We can use the normal distribution to calculate this probability. We first calculate the z-score for this value as follows:

z = (31.95 - 31.9) / (0.163 / √(45)) = 1.77

Using a standard normal table or calculator, we can find the probability that a z-score is greater than or equal to 1.77. This probability is approximately 0.0384.

b) To solve this problem, we need to use the normal approximation to the binomial distribution. Since each eraser is either "good" or "bad", the number of "good" erasers that the unit finds each day follows a binomial distribution with parameters n = 50 and p = probability of finding a "good" eraser = (32.3 - 31.7)/(32.3 - 31.5) = 0.5.

Now, we need to find the probability that, on average, the unit finds at least 37.2 "good" erasers per day. We can use the normal distribution to calculate this probability. We first calculate the z-score for this value as follows:

z = (37.2 - 25) / 25 = 0.488

Using a standard normal table or calculator, we can find the probability that a z-score is greater than or equal to 0.488. This probability is approximately 0.3133.

To know more about probability here

https://brainly.com/question/11234923

#SPJ4

The true statements are:

A valid conclusion is :

The range of a data set is the difference between the highest and lowest values in the set.

To calculate the range, you subtract the smallest value from the largest value.

The mean of a data set, also called the average, is the sum of all the values in the set divided by the total number of values in the set.

To calculate the mean, you add up all the values and divide by the total number of values.

Learn more about the range and mean at: https://brainly.com/question/30094086

#SPJ1

At point (-43,0), f has a maximum. At point (0,4), f has a minimum. At point (463,0), f has a maximum. At point (0,0), f may have a critical point. none of the given points are critical points of the function f (x, y) = xy + 33 - 48y.

Hi! To analyze the critical points of the function f(x, y) = xy + 33 - 48y, we first need to find the partial derivatives with respect to x and y:

fx = ∂f/∂x = y
fy = ∂f/∂y = x - 48

Now, we can analyze the given points:

1. (-43, 0)
At this point, fx = 0 and fy = -48. Since both partial derivatives are not equal to 0, this point is not a critical point.

2. (0, 4)
At this point, fx = 4 and fy = 0. Again, both partial derivatives are not equal to 0, so this is not a critical point.

3. (463, 0)
At this point, fx = 0 and fy = 463 - 48 = 415. Since both partial derivatives are not equal to 0, this is not a critical point.

4. (0, 0)
At this point, fx = 0 and fy = -48. Since both partial derivatives are not equal to 0, this is not a critical point.

5. (0, -4)
At this point, fx = -4 and fy = -48. Again, both partial derivatives are not equal to 0, so this is not a critical point.

In summary, none of the given points are critical points of the function f(x, y) = xy + 33 - 48y.

Learn more about critical point here:

brainly.com/question/30724817

#SPJ11

To find the arc length between each car on the Ferris Wheel, we need to first find the measure of the central angle formed by each car.

The Ferris Wheel has a diameter of 150 ft, which means its radius is half that of 75 ft. We can use the formula s = rθ, where s is the arc length, r is the radius, and θ is the central angle in radians.

Since we have 25 cars on the Ferris Wheel, we can divide the circle into 25 equal parts, each representing the central angle formed by each car.

The total central angle of the circle is 2π radians (or 360 degrees), so each central angle formed by each car is:

(2π radians) / 25 = 0.2513 radians (rounded to four decimal places)

Now we can use this central angle and the radius of the Ferris Wheel to find the arc length between each car:

s = rθ
s = 75 ft * 0.2513
s = 18.8475 ft (rounded to four decimal places)

Therefore, the approximate arc length between each car on the Ferris Wheel is approximately 18.85 ft.

Learn more about Ferris Wheel at https://brainly.com/question/26887939

#SPJ11

The rate at which salt enters the tank at time t is constant & equal to 8 lb/min,

The rate at which salt enters the tank at time t is equal to the product of the concentration of the incoming brine & the rate at which it enters the tank

At time t, the amount of salt in the tank is y(t), & the volume of the brine in the tank is V(t)-

Therefore, the concentration of salt in the tank at time t is:-

c(t) = y(t) / V(t)

The rate at which brine enters the tank at time t is 4 gal/min, & the concentration of salt in the incoming brine is 2 lb/gal

So the rate at which salt enters the tank at time t is:-

2 lb/gal x 4 gal/min = 8 lb/min

Therefore, the rate at which salt enters the tank at time t is constant & equal to 8 lb/min, regardless of how much salt is already in the tank

To know more about salt enter problems-

brainly.com/question/16867287

#SPJ4

The value of n which is the number of frogs Heather has is 6.

The number of frogs Heather has is calculated as follows;

let the number of frogs Heather has = n

So Ava has 2 fogs, which is equal to 1/3 n.

The value of n which is the number of frogs Heather has is calculated as follows;

(1/3) n = 2

multiply both sides by 3;

n = 3 x 2

n = 6

The division using a diagram, is determined as;

    0         0

    I           I

    I           I

    I            I

Learn more about divisions here: https://brainly.com/question/25289437

#SPJ1

The probability of the event BE falling on a random point AK is 4/11

A probability event can be defined as a set of outcomes of an experiment. In other words, an event in probability is the subset of the respective sample space.

In this problem, we need to determine our sample space;

The sample space = 11

The number of favorable outcomes = 4

The probability of a random point on AK to be on BE will be;

P = 4 / 11

Learn more on probability here;

https://brainly.com/question/24756209

#SPJ1

Answer:

$15.92

Step-by-step explanation:

We Know

2 liters of Gatorade cost $3.98

How much do 8 liters cost?

We take

3.98 x 4 = $15.92

So, 8 liters cost $15.92

The possible dimensions of the rectangular prism having volume  =  12 in³,  are  Length = 2 in, width = 3 in, height = 2/3 in, and Length = 1 in, width = 12 in, height = 1/12 in.

To find the possible dimensions of the prism, we need to consider that the volume of a rectangular prism is given by the formula V = lwh, where l, w, and h are the length, width, and height of the prism, respectively.

Since the volume of the prism is given as 12 in³, we can write: 12 = lwh
Now, we need to find two sets of dimensions that satisfy this equation, where one of the dimensions is a fraction.

Let's try the first set of dimensions:
l = 2 in
w = 3 in
h = 2/3 in

Plugging these values into the formula for the volume, we get:
V = lwh
V = 2 in × 3 in × 2/3 in
V = 4 in³

This confirms that the volume of the prism is indeed 12 in³, and that one of the dimensions (height) is a fraction.

Now, let's try another set of dimensions:
l = 1 in
w = 12 in
h = 1/12 in

Again, plugging these values into the formula for the volume, we get:
V = lwh
V = 1 in × 12 in × 1/12 in
V = 1 in³

This set of dimensions also satisfies the condition that the volume of the prism is 12 in³, with one of the dimensions (height) being a fraction.

Therefore, the possible dimensions of the prism are:
- Length = 2 in, width = 3 in, height = 2/3 in
- Length = 1 in, width = 12 in, height = 1/12 in.

To know more about prism refer here:

https://brainly.com/question/29077780#

#SPJ11

a) The mean monthly rainfall amount for City A is 334.17 inches and for City B is 5.83 inches.

b) The MAD for City A is 464.28 inches and for City B is 0.46 inches.

c) The median for City A is 5 inches and for City B is 6 inches.

(a) To find the mean monthly rainfall amount for each city, we need to add up all the rainfall amounts and divide by the number of months:

For City A: (5 + 2.5 + 6 + 2008.5 + 5 + 3) / 6 = 334.17 inches

For City B: (7 + 6 + 5.5 + 6.5 + 5 + 6) / 6 = 5.83 inches

(b) To find the mean absolute deviation (MAD) for each city, we need to find the absolute deviations from the mean for each data point, then calculate the average of those absolute deviations:

For City A:

Mean = 334.17 inches

Absolute deviations from the mean: |5 - 334.17| = 329.17, |2.5 - 334.17| = 331.67, |6 - 334.17| = 328.17, |2008.5 - 334.17| = 1674.33, |5 - 334.17| = 328.17, |3 - 334.17| = 331.17

MAD = (329.17 + 331.67 + 328.17 + 1674.33 + 328.17 + 331.17) / 6 = 464.28 inches

For City B:

Mean = 5.83 inches

Absolute deviations from the mean: |7 - 5.83| = 1.17, |6 - 5.83| = 0.17, |5.5 - 5.83| = 0.33, |6.5 - 5.83| = 0.67, |5 - 5.83| = 0.83, |6 - 5.83| = 0.17

MAD = (1.17 + 0.17 + 0.33 + 0.67 + 0.83 + 0.17) / 6 = 0.46 inches

(c) To find the median for each city, we need to arrange the data points in order and find the middle value:

For City A: {2.5, 3, 5, 5, 6, 2008.5}

Median = 5 inches

For City B: {5, 5.5, 6, 6, 6.5, 7}

Median = 6 inches

To learn more about MAD here:

https://brainly.com/question/10528201

#SPJ4

Answer:

The perfect factored square trinomial that is equivalent to the expression x^2 + 8x + 16 is:

(x + 4)^2

To see why this is the case, you can expand the expression (x + 4)^2 using the FOIL method:

(x + 4)^2 = (x + 4) * (x + 4)

= x^2 + 4x + 4x + 16

= x^2 + 8x + 16

So, x^2 + 8x + 16 can be factored as (x + 4)^2, which is a perfect square trinomial.

The probability of rolling any number other than 4 on a number cube with sides numbered 1, 2, 3, 4, 5, and 6 is 5/6, which can be written as a fraction in simplest form.

The complement of rolling a 4 on a number cube with sides numbered 1, 2, 3, 4, 5, and 6 is rolling any number other than 4, which includes rolling a 1, 2, 3, 5, or 6.

To find the probability of the complement, we need to add up the probabilities of rolling each of these numbers.

Since each number has an equal chance of being rolled, we can find the probability of rolling each number by dividing 1 by the total number of possible outcomes (which is 6, since there are six sides on the cube).

Then, we can add up the probabilities of rolling each of the five numbers in the complement:

P(rolling a 1, 2, 3, 5, or 6) = P(rolling a 1) + P(rolling a 2) + P(rolling a 3) + P(rolling a 5) + P(rolling a 6)

P(rolling any number other than 4) = 1 - P(rolling a 4)

P(rolling any number other than 4) = 1 - 1/6 = 5/6

Therefore, the probability of rolling any number other than 4 on a number cube with sides numbered 1, 2, 3, 4, 5, and 6 is 5/6, which can be written as a fraction in simplest form.

Read more about probabilities at:

brainly.com/question/11234923

#SPJ1

The rate of the boat in still water is 5 miles per hour and rate of the boat in current is 3 miles per hour.

Let us represent the rate of boat in still water hence and rate of boat in current be y. Also, we know that speed = distance/time. Hence, keep the values in formula -

Converting mixed fraction to fraction, time = 3/2 hour

Time = 1.5 hour

1.5 (x + y) = 12 : equation 1

Divide the equation 1 by 3

0.5 (x + y) = 4 : equation 2

6 (x - y) = 12 : equation 3

Divide the equation 3 by 6

(x - y) = 2

x = 2 + y : equation 4

Keep the value of x from equation 4 in equation 2

0.5 (2 + y + y) = 4

1 + y = 4

y = 4 - 1

y = 3 miles/ hour

Keep the value y in equation 4 to get x

x = 2 + 3

x = 5 miles per hour

The rate in still water and current is 5 and 3 miles per hour.

Learn more about rate -

https://brainly.com/question/4800946

#SPJ4

The complete question is-

It takes a boat 1 (1/2) hr to go 12 mi downstream, and 6 hr to return. Find the rate of the boat in still water and the rate of the current.

To find the maximums and minimums of the function f(x,y)=x^2+y^2+xy in the region {(x,y): x^2+y^2<=1}, we need to use the method of Lagrange multipliers.

First, we need to find the gradient of the function and set it equal to the gradient of the constraint (which is the equation of the circle x^2+y^2=1).

∇f(x,y) = <2x+y, 2y+x>
∇g(x,y) = <2x, 2y>

So, we have the equations:
2x+y = 2λx
2y+x = 2λy
x^2+y^2 = 1

Simplifying the first two equations, we get:
y = (2λ-2)x
x = (2λ-2)y

Substituting these into the equation of the circle, we get:
x^2+y^2 = 1
(2λ-2)^2 x^2 + (2λ-2)^2 y^2 = 1
(2λ-2)^2 (x^2+y^2) = 1
(2λ-2)^2 = 1/(x^2+y^2)

Solving for λ, we get:
λ = 1/2 or λ = 3/2

If λ = 1/2, then we get x = -y and x^2+y^2=1, which gives us the critical points (-1/√2, 1/√2) and (1/√2, -1/√2). We can plug these into the function to find that f(-1/√2, 1/√2) = f(1/√2, -1/√2) = -1/4.

If λ = 3/2, then we get x = 2y and x^2+y^2=1, which gives us the critical point (2/√5, 1/√5). We can plug this into the function to find that f(2/√5, 1/√5) = 3/5.

Therefore, the local maximum is (2/√5, 1/√5) with a value of 3/5, the local minimum is (-1/√2, 1/√2) and (1/√2, -1/√2) with a value of -1/4, and the absolute maximum is also (2/√5, 1/√5) with a value of 3/5, and the absolute minimum is on the border, which occurs at (0,1) and (0,-1) with a value of 0.

There are no critical points in the interior of the disk (not the border) that are not extremes or saddle points.
(i) Local extrema:
To find the local extrema, we first find the partial derivatives of f(x, y) with respect to x and y:

f_x = 2x + y
f_y = 2y + x

Set both partial derivatives equal to zero to find critical points:

2x + y = 0
2y + x = 0

Solving this system of equations, we find that the only critical point is (0, 0).

(ii) Absolute extrema:
To determine whether the critical point is an absolute maximum, minimum, or saddle point, we must examine the second partial derivatives:

f_xx = 2
f_yy = 2
f_xy = f_yx = 1

Compute the discriminant: D = f_xx * f_yy - (f_xy)^2 = 2 * 2 - 1^2 = 3

Since D > 0 and f_xx > 0, the point (0, 0) is an absolute minimum of the function.

(iii) Critical points and their classification:
The only critical point in the interior of the disk is (0, 0). As determined earlier, this point is an absolute minimum. No saddle points or other extrema are present within the interior of the disk.

To find any extrema on the boundary of the disk (x^2 + y^2 = 1), we use the method of Lagrange multipliers. However, as the boundary is not part of the domain specified in the question, we will not delve into that here.

Visit here to learn more about equation  : https://brainly.com/question/29538993
#SPJ11

The area under the standard normal distribution curve between z = 0 and z = 0.98 is:

                         0.8365 - 0.5000 = 0.3365

To find the area under the standard normal distribution curve between z = 0 and z = 0.98, we can use a standard normal distribution table or a calculator that can compute normal probabilities.

Using a standard normal distribution table, we can look up the area corresponding to a z-score of 0 and a z-score of 0.98 separately and then subtract the two areas to find the area between them.

The area under the standard normal distribution curve to the left of z = 0 is 0.5000 (by definition). The area under the curve to the left of z = 0.98 is 0.8365 (from the standard normal distribution table).

So the area under the standard normal distribution curve between z=0 and z=0.98 is approximately 0.3365.

To know more about area under curve refer here

https://brainly.com/question/40445978#

#SPJ11

If he put 40 red balls, 55 purple balls, 45 yellow balls, and 60 green balls into the ball pit. while his sister is playing, one ball rolls out of the pit. Therefore, the probability that the ball that rolled out of the pit is red is 0.2.

The probability of selecting a red ball from the ball pit can be found by dividing the number of red balls by the total number of balls in the pit.

Total number of balls = 40 + 55 + 45 + 60 = 200

Probability of selecting a red ball = Number of red balls / Total number of balls

Probability of selecting a red ball = 40 / 200

Probability of selecting a red ball = 0.2

Therefore, the probability that the ball that rolled out of the pit is red is 0.2.

To learn more about “probability” refer to the https://brainly.com/question/13604758

#SPJ11

The solution to the given equation which is log₃(1/9) = 2x - 1 is equal to x = -1/2.

To solve the equation log₃(1/9) = 2x - 1, we need to isolate the variable x on one side of the equation. We can start by using the logarithm property that states that the logarithm of a number to a base is equal to the exponent to which the base must be raised to obtain that number. In other words, log₃(1/9) = x if and only if [tex]3^x[/tex] = 1/9.

So, let's rewrite the given equation using this property as follows:

[tex]3^{(log(1/9))[/tex] = [tex]3^{2x-1[/tex]

Simplifying the left-hand side using the logarithm property, we get:

1/9 = [tex]3^{(2x - 1)[/tex]

Now, we can solve for x by taking the logarithm of both sides to base 3:

log₃(1/9) = log₃([tex]3^{(2x - 1)[/tex])

-2 = (2x - 1) * log₃(3)

-2 = 2x - 1

2x = -1

x = -1/2

To learn more about logarithm click on,

https://brainly.com/question/23936575

#SPJ1

Answer: -10.57

Step-by-step explanation:

Answer:

0.25 years

Step-by-step explanation:

Penelope invested $89,000 in an account paying an interest rate of 6⅜% compounded continuously.

To calculate the time it would take Penelope's money to double, use the continuous compounding interest formula.

[tex]\boxed{\begin{minipage}{8.5 cm}\underline{Continuous Compounding Interest Formula}\\\\$ A=Pe^{rt}$\\\\where:\\\\ \phantom{ww}$\bullet$ $A =$ final amount \\\phantom{ww}$\bullet$ $P =$ principal amount \\\phantom{ww}$\bullet$ $e =$ Euler's number (constant) \\\phantom{ww}$\bullet$ $r =$ annual interest rate (in decimal form) \\\phantom{ww}$\bullet$ $t =$ time (in years) \\\end{minipage}}[/tex]

As the principal amount is doubled, then A = 2P.

Given interest rate:

Substitute A = 2P and r = 0.06375 into the continuous compounding interest formula and solve for t:

[tex]\implies 2P=Pe^{0.06375t}[/tex]

[tex]\implies 2=e^{0.06375t}[/tex]

[tex]\implies \ln 2=\ln e^{0.06375t}[/tex]

[tex]\implies \ln 2=0.06375t\ln e[/tex]

[tex]\implies \ln 2=0.06375t(1)[/tex]

[tex]\implies \ln 2=0.06375t[/tex]

[tex]\implies t=\dfrac{\ln 2}{0.06375}[/tex]

[tex]\implies t=10.872896949...[/tex]

Therefore, it will take 10.87 years for Penelope's investment to double.

[tex]\hrulefill[/tex]

Samir invested $89,000 in an account paying an interest rate of 6¹/₄% compounded monthly.

To calculate the time it would take Samir's money to double, use the compound interest formula.

[tex]\boxed{\begin{minipage}{8.5 cm}\underline{Compound Interest Formula}\\\\$ A=P\left(1+\frac{r}{n}\right)^{nt}$\\\\where:\\\\ \phantom{ww}$\bullet$ $A =$ final amount \\ \phantom{ww}$\bullet$ $P =$ principal amount \\ \phantom{ww}$\bullet$ $r =$ interest rate (in decimal form) \\ \phantom{ww}$\bullet$ $n =$ number of times interest is applied per year \\ \phantom{ww}$\bullet$ $t =$ time (in years) \\ \end{minipage}}[/tex]

As the principal amount is doubled, then A = 2P.

Given values:

Substitute the values into the formula and solve for t:

[tex]\implies 2P=P\left(1+\dfrac{0.0625}{12}\right)^{12t}[/tex]

[tex]\implies 2=\left(1+\dfrac{0.0625}{12}\right)^{12t}[/tex]

[tex]\implies 2=\left(1+0.005208333...\right)^{12t}[/tex]

[tex]\implies 2=\left(1.005208333...\right)^{12t}[/tex]

[tex]\implies \ln 2=\ln \left(1.005208333...\right)^{12t}[/tex]

[tex]\implies \ln 2=12t \ln \left(1.005208333...\right)[/tex]

[tex]\implies t=\dfrac{\ln 2}{12 \ln \left(1.005208333...\right)}[/tex]

[tex]\implies t=11.1192110...[/tex]

Therefore, it will take 11.12 years for Samir's investment to double.

[tex]\hrulefill[/tex]

To calculate how much longer it would take for Samir's money to double than for Penelope's money to double, subtract the value of t for Penelope from the value of t for Samir:

[tex]\begin{aligned}\implies t_{\sf Samir}-t_{\sf Penelope}&=11.1192110......-10.872896949...\\&= 0.246314066...\\&=0.25\; \sf years\;(nearest\;hundredth)\end{aligned}[/tex]

Therefore, it would take 0.25 years longer for Samir's money to double than for Penelope's money to double.

The value of k is 11 at which a and 6 will be orthogonal (form a 90 degree angle).

To find the value of k that makes vectors a and 6 orthogonal, we need to use the dot product formula:

a · 6 = 2(-1) + 3(5) + (-1)k = 0

Simplifying the above equation, we get:

-2 + 15 - k = 0

Combining like terms, we get:

13 - k = 0

Therefore, k = 13.

However, we need to check if this value of k makes vectors a and 6 orthogonal.

a · 6 = 2(-1) + 3(5) + (-1)(13) = 0

The dot product is zero, which means vectors a and 6 are orthogonal.

Thus, the final answer is k = 11.

For more questions like Vector click the link below:

https://brainly.com/question/29740341

#SPJ11