Answer:
9
Step-by-step explanation:
Given
p(x) = 5x² - 3x + 7 ← substitute x = 1
p(1) = 5(1)² - 3(1) + 7 = 5(1) - 3(1) + 7 = 5 - 3 + 7 = 9
Answer:
![k = 1](https://tex.z-dn.net/?f=k%20%3D%201)
![P(x > 3y) = \frac{2}{3}](https://tex.z-dn.net/?f=P%28x%20%3E%203y%29%20%3D%20%5Cfrac%7B2%7D%7B3%7D)
Step-by-step explanation:
Given
![f \left(x,y \right) = \left{ \begin{array} { l l } { k , } & { 0 \leq x} \leq 2,0 \leq y \leq 1,2 y \leq x } & { \text 0, { elsewhere. } } \end{array} \right.](https://tex.z-dn.net/?f=f%20%5Cleft%28x%2Cy%20%5Cright%29%20%3D%20%5Cleft%7B%20%5Cbegin%7Barray%7D%20%7B%20l%20l%20%7D%20%7B%20k%20%2C%20%7D%20%26%20%7B%200%20%5Cleq%20x%7D%20%5Cleq%202%2C0%20%5Cleq%20y%20%5Cleq%201%2C2%20y%20%20%5Cleq%20x%20%7D%20%20%26%20%7B%20%5Ctext%200%2C%20%7B%20elsewhere.%20%7D%20%7D%20%5Cend%7Barray%7D%20%5Cright.)
Solving (a):
Find k
To solve for k, we use the definition of joint probability function:
![\int\limits^a_b \int\limits^a_b {f(x,y)} \, = 1](https://tex.z-dn.net/?f=%5Cint%5Climits%5Ea_b%20%5Cint%5Climits%5Ea_b%20%7Bf%28x%2Cy%29%7D%20%5C%2C%20%3D%201)
Where
![{ 0 \leq x} \leq 2,0 \leq y \leq 1,2 y \leq x }](https://tex.z-dn.net/?f=%7B%200%20%5Cleq%20x%7D%20%5Cleq%202%2C0%20%5Cleq%20y%20%5Cleq%201%2C2%20y%20%20%5Cleq%20x%20%7D)
Substitute values for the interval of x and y respectively
So, we have:
![\int\limits^2_{0} \int\limits^{x/2}_{0} {k\ dy\ dx} \, = 1](https://tex.z-dn.net/?f=%5Cint%5Climits%5E2_%7B0%7D%20%5Cint%5Climits%5E%7Bx%2F2%7D_%7B0%7D%20%7Bk%5C%20dy%5C%20dx%7D%20%5C%2C%20%3D%201)
Isolate k
![k \int\limits^2_{0} \int\limits^{x/2}_{0} {dy\ dx} \, = 1](https://tex.z-dn.net/?f=k%20%5Cint%5Climits%5E2_%7B0%7D%20%5Cint%5Climits%5E%7Bx%2F2%7D_%7B0%7D%20%7Bdy%5C%20dx%7D%20%5C%2C%20%3D%201)
Integrate y, leave x:
![k \int\limits^2_{0} y {dx} \, [0,x/2]= 1](https://tex.z-dn.net/?f=k%20%5Cint%5Climits%5E2_%7B0%7D%20y%20%7Bdx%7D%20%5C%2C%20%5B0%2Cx%2F2%5D%3D%201)
Substitute 0 and x/2 for y
![k \int\limits^2_{0} (x/2 - 0) {dx} \,= 1](https://tex.z-dn.net/?f=k%20%5Cint%5Climits%5E2_%7B0%7D%20%28x%2F2%20-%200%29%20%7Bdx%7D%20%5C%2C%3D%201)
![k \int\limits^2_{0} \frac{x}{2} {dx} \,= 1](https://tex.z-dn.net/?f=k%20%5Cint%5Climits%5E2_%7B0%7D%20%5Cfrac%7Bx%7D%7B2%7D%20%7Bdx%7D%20%5C%2C%3D%201)
Integrate x
![k * \frac{x^2}{2*2} [0,2]= 1](https://tex.z-dn.net/?f=k%20%2A%20%5Cfrac%7Bx%5E2%7D%7B2%2A2%7D%20%5B0%2C2%5D%3D%201)
![k * \frac{x^2}{4} [0,2]= 1](https://tex.z-dn.net/?f=k%20%2A%20%5Cfrac%7Bx%5E2%7D%7B4%7D%20%5B0%2C2%5D%3D%201)
Substitute 0 and 2 for x
![k *[ \frac{2^2}{4} - \frac{0^2}{4} ]= 1](https://tex.z-dn.net/?f=k%20%2A%5B%20%5Cfrac%7B2%5E2%7D%7B4%7D%20-%20%5Cfrac%7B0%5E2%7D%7B4%7D%20%5D%3D%201)
![k *[ \frac{4}{4} - \frac{0}{4} ]= 1](https://tex.z-dn.net/?f=k%20%2A%5B%20%5Cfrac%7B4%7D%7B4%7D%20-%20%5Cfrac%7B0%7D%7B4%7D%20%5D%3D%201)
![k *[ 1-0 ]= 1](https://tex.z-dn.net/?f=k%20%2A%5B%201-0%20%5D%3D%201)
![k *[ 1]= 1](https://tex.z-dn.net/?f=k%20%2A%5B%201%5D%3D%201)
![k = 1](https://tex.z-dn.net/?f=k%20%3D%201)
Solving (b): ![P(x > 3y)](https://tex.z-dn.net/?f=P%28x%20%3E%203y%29)
We have:
![f(x,y) = k](https://tex.z-dn.net/?f=f%28x%2Cy%29%20%3D%20k)
Where ![k = 1](https://tex.z-dn.net/?f=k%20%3D%201)
![f(x,y) = 1](https://tex.z-dn.net/?f=f%28x%2Cy%29%20%3D%201)
To find
, we use:
![\int\limits^a_b \int\limits^a_b {f(x,y)}](https://tex.z-dn.net/?f=%5Cint%5Climits%5Ea_b%20%5Cint%5Climits%5Ea_b%20%7Bf%28x%2Cy%29%7D)
So, we have:
![P(x > 3y) = \int\limits^2_0 \int\limits^{y/3}_0 {f(x,y)} dxdy](https://tex.z-dn.net/?f=P%28x%20%3E%203y%29%20%3D%20%5Cint%5Climits%5E2_0%20%5Cint%5Climits%5E%7By%2F3%7D_0%20%7Bf%28x%2Cy%29%7D%20dxdy)
![P(x > 3y) = \int\limits^2_0 \int\limits^{y/3}_0 {1} dxdy](https://tex.z-dn.net/?f=P%28x%20%3E%203y%29%20%3D%20%5Cint%5Climits%5E2_0%20%5Cint%5Climits%5E%7By%2F3%7D_0%20%7B1%7D%20dxdy)
![P(x > 3y) = \int\limits^2_0 \int\limits^{y/3}_0 dxdy](https://tex.z-dn.net/?f=P%28x%20%3E%203y%29%20%3D%20%5Cint%5Climits%5E2_0%20%5Cint%5Climits%5E%7By%2F3%7D_0%20%20dxdy)
Integrate x leave y
![P(x > 3y) = \int\limits^2_0 x [0,y/3]dy](https://tex.z-dn.net/?f=P%28x%20%3E%203y%29%20%3D%20%5Cint%5Climits%5E2_0%20%20x%20%5B0%2Cy%2F3%5Ddy)
Substitute 0 and y/3 for x
![P(x > 3y) = \int\limits^2_0 [y/3 - 0]dy](https://tex.z-dn.net/?f=P%28x%20%3E%203y%29%20%3D%20%5Cint%5Climits%5E2_0%20%20%5By%2F3%20-%200%5Ddy)
![P(x > 3y) = \int\limits^2_0 y/3\ dy](https://tex.z-dn.net/?f=P%28x%20%3E%203y%29%20%3D%20%5Cint%5Climits%5E2_0%20%20y%2F3%5C%20dy)
Integrate
![P(x > 3y) = \frac{y^2}{2*3} [0,2]](https://tex.z-dn.net/?f=P%28x%20%3E%203y%29%20%3D%20%5Cfrac%7By%5E2%7D%7B2%2A3%7D%20%5B0%2C2%5D)
![P(x > 3y) = \frac{y^2}{6} [0,2]\\](https://tex.z-dn.net/?f=P%28x%20%3E%203y%29%20%3D%20%5Cfrac%7By%5E2%7D%7B6%7D%20%5B0%2C2%5D%5C%5C)
Substitute 0 and 2 for y
![P(x > 3y) = \frac{2^2}{6} -\frac{0^2}{6}](https://tex.z-dn.net/?f=P%28x%20%3E%203y%29%20%3D%20%5Cfrac%7B2%5E2%7D%7B6%7D%20-%5Cfrac%7B0%5E2%7D%7B6%7D)
![P(x > 3y) = \frac{4}{6} -\frac{0}{6}](https://tex.z-dn.net/?f=P%28x%20%3E%203y%29%20%3D%20%5Cfrac%7B4%7D%7B6%7D%20-%5Cfrac%7B0%7D%7B6%7D)
![P(x > 3y) = \frac{4}{6}](https://tex.z-dn.net/?f=P%28x%20%3E%203y%29%20%3D%20%5Cfrac%7B4%7D%7B6%7D)
![P(x > 3y) = \frac{2}{3}](https://tex.z-dn.net/?f=P%28x%20%3E%203y%29%20%3D%20%5Cfrac%7B2%7D%7B3%7D)
Answer:
The last answer choice is correct, I am pretty sure.
Just go on the calculator (like Desmos) and just use the decimals to determine which one is true.
The amount that will be expected to be paid for the bonds that are bought will be C. $3,318.33
<h3>How to calculate the amount of bonds?</h3>
From the information given, the bonds from the city of tavel gorge worth $1,000 each are selling at 110.611 and Sean wishes to purchase three such bonds.
Therefore, the amount for the bonds will be:
= 1110.611 × 3
= 3,318.33
In conclusion, the correct option is C.
Learn more about bonds on:
brainly.com/question/2775110
#SPJ4
I’m pretty sure the answer is (2,1)