Answer:
85/2 or 42.5 ft²
Step-by-step explanation:
A = l x w
A = 7.5 (5 2/3)
= 15/2 (17/3)
= 255/6
= 85/2 ft² or 42.5 ft²
Answer:
a) P ( 3 ≤X≤ 5 ) = 0.02619
b) E(X) = 1
Step-by-step explanation:
Given:
- The CDF of a random variable X = { 0 , 1 , 2 , 3 , .... } is given as:
Find:
a.Calculate the probability that 3 ≤X≤ 5
b) Find the expected value of X, E(X), using the fact that. (Hint: You will have to evaluate an infinite sum, but that will be easy to do if you notice that
Solution:
- The CDF gives the probability of (X < x) for any value of x. So to compute the P ( 3 ≤X≤ 5 ) we will set the limits.
![F(X) = P ( 3=](https://tex.z-dn.net/?f=F%28X%29%20%3D%20P%20%28%203%3D%3CX%20%3D%3C%205%29%20%3D%20%5B1%20-%20%5Cfrac%7B1%7D%7B%28x%2B1%29%2A%28x%2B2%29%7D%5D%5Climits%5E5_3%5C%5C%5C%5CF%28X%29%20%3D%20P%20%28%203%3D%3CX%20%3D%3C%205%29%20%3D%20%5B-%5Cfrac%7B1%7D%7B%285%2B1%29%2A%285%2B2%29%7D%20%2B%20%5Cfrac%7B1%7D%7B%283%2B1%29%2A%283%2B2%29%7D%7D%5C%5C%5C%5CF%28X%29%20%3D%20P%20%28%203%3D%3CX%20%3D%3C%205%29%20%3D%20%5B-%5Cfrac%7B1%7D%7B%2842%29%7D%20%2B%20%5Cfrac%7B1%7D%7B%2820%29%7D%7D%5D%5C%5C%5C%5CF%28X%29%20%3D%20P%20%28%203%3D%3CX%20%3D%3C%205%29%20%3D%200.02619)
- The Expected Value can be determined by sum to infinity of CDF:
E(X) = Σ ( 1 - F(X) )
![E(X) = \frac{1}{(x+1)*(x+2)} = \frac{1}{(x+1)} - \frac{1}{(x+2)} \\\\= \frac{1}{(1)} - \frac{1}{(2)}\\\\= \frac{1}{(2)} - \frac{1}{(3)} \\\\= \frac{1}{(3)} - \frac{1}{(4)}\\\\= ............................................\\\\= \frac{1}{(n)} - \frac{1}{(n+1)}\\\\= \frac{1}{(n+1)} - \frac{1}{(n+ 2)}](https://tex.z-dn.net/?f=E%28X%29%20%3D%20%5Cfrac%7B1%7D%7B%28x%2B1%29%2A%28x%2B2%29%7D%20%3D%20%5Cfrac%7B1%7D%7B%28x%2B1%29%7D%20-%20%5Cfrac%7B1%7D%7B%28x%2B2%29%7D%20%5C%5C%5C%5C%3D%20%5Cfrac%7B1%7D%7B%281%29%7D%20-%20%5Cfrac%7B1%7D%7B%282%29%7D%5C%5C%5C%5C%3D%20%5Cfrac%7B1%7D%7B%282%29%7D%20-%20%5Cfrac%7B1%7D%7B%283%29%7D%20%5C%5C%5C%5C%3D%20%20%5Cfrac%7B1%7D%7B%283%29%7D%20-%20%5Cfrac%7B1%7D%7B%284%29%7D%5C%5C%5C%5C%3D%20............................................%5C%5C%5C%5C%3D%20%20%5Cfrac%7B1%7D%7B%28n%29%7D%20-%20%5Cfrac%7B1%7D%7B%28n%2B1%29%7D%5C%5C%5C%5C%3D%20%20%5Cfrac%7B1%7D%7B%28n%2B1%29%7D%20-%20%5Cfrac%7B1%7D%7B%28n%2B%202%29%7D)
E(X) = Limit n->∞ [1 - 1 / ( n + 2 ) ]
E(X) = 1
2+2 = 4. Bro it was so hard. Did i helped you?
Answer:
Step-by-step explanation:
5/1 - 5/7
35/7 - 5/7
= 30/7 = 4 2/7 lb
Multiply the denominators, 7 by 5,and 1 by 7. When you have the same denominator in each fraction you can subtract. (7x4= 28, 30-28= 2)
Answer:
![(5\pi-11.6)\ ft^{2}](https://tex.z-dn.net/?f=%285%5Cpi-11.6%29%5C%20ft%5E%7B2%7D)
Step-by-step explanation:
we know that
The area of the shaded region is equal to the area of the sector minus the area of the triangle
step 1
Find the area of the circle
the area of the circle is equal to
![A=\pi r^{2}](https://tex.z-dn.net/?f=A%3D%5Cpi%20r%5E%7B2%7D)
we have
![r=5\ ft](https://tex.z-dn.net/?f=r%3D5%5C%20ft)
substitute
![A=\pi (5)^{2}](https://tex.z-dn.net/?f=A%3D%5Cpi%20%285%29%5E%7B2%7D)
![A=25\pi\ ft^{2}](https://tex.z-dn.net/?f=A%3D25%5Cpi%5C%20ft%5E%7B2%7D)
step 2
Find the area of the sector
we know that
The area of the circle subtends a central angle of 360 degrees
so
by proportion find out the area of a sector by a central angle of 72 degrees
![\frac{25\pi}{360}=\frac{x}{72}\\ \\x=72*25\pi /360\\ \\x=5\pi\ ft^{2}](https://tex.z-dn.net/?f=%5Cfrac%7B25%5Cpi%7D%7B360%7D%3D%5Cfrac%7Bx%7D%7B72%7D%5C%5C%20%5C%5Cx%3D72%2A25%5Cpi%20%2F360%5C%5C%20%5C%5Cx%3D5%5Cpi%5C%20ft%5E%7B2%7D)
step 3
Find the area of triangle
The area of the triangle is equal to
![A=\frac{1}{2}(2.9+2.9)(4)= 11.6\ ft^{2}](https://tex.z-dn.net/?f=A%3D%5Cfrac%7B1%7D%7B2%7D%282.9%2B2.9%29%284%29%3D%2011.6%5C%20ft%5E%7B2%7D)
step 4
Find the area of the shaded region
Subtract the area of the triangle from the area of the sector
![(5\pi-11.6)\ ft^{2}](https://tex.z-dn.net/?f=%285%5Cpi-11.6%29%5C%20ft%5E%7B2%7D)