Answer:
Step-by-step explanation:
Given that:
X(t) = be the number of customers that have arrived up to time t.
... = the successive arrival times of the customers.
(a)
Then; we can Determine the conditional mean E[W1|X(t)=2] as follows;
Now 
(b) We can Determine the conditional mean E[W3|X(t)=5] as follows;
Now; 
(c) Determine the conditional probability density function for W2, given that X(t)=5.
So ; the conditional probability density function of 
given that X(t)=5 is:
Not much can be done without knowing what
is, but at the least we can set up the integral.
First parameterize the pieces of the contour:
where
and
. You have
and so the work is given by the integral
My guess is that you're doing the Law of Cosines? You have everything you need for that except the angle theta, which is the thing you need to find. It's set up like this: (8)^2 = (10)^2 + (5)^2 -[2(10)(5)cos A] I used A instead of theta. Doing that math, you have: 64 = 100 + 25 -[ 100 cos A]; 64 = 125 - 100 cos A;
-61 = - 100 cos A; -61 / -100 = cos A; .61 = cos A. Now use your inverse function on your calculator to find cos^-1(.61) and that equals 52.4
600 feet of tape because 4 +4 for two sides of the window is 8 and 3+ 3 is 6, 14 plus the foot of overlap is 15 x 40 is 600.
