I need some help with "law of total expectation".
Sorry for my English, I don't know the right English expressions.
The Problem is:
People come (show in) with with Poisson rate of 10 people per hour.
There is a 0.2 chance that a person will give money to a beggar sitting in the corner.
The...
I have the following question:
2 persons shoot it each other. Person A shoots at Person B, if A misses, B shoots at A and so on.
The Game continues until one of them hits the other one.
Probability that A hits B is P1 ,and probability that B hits A is P2.
I need to find the E[X].
They give...
why do you multiply 2*pi*Rsin(theta) by Rdtheta?
We need area so we must find the integral from circumference...
And what is the logic taking circle 2*pi*Rsin(theta) as element of area?
Why can't i just use 4\pi r^{2} as the area of the shell?
A half spherical shell as seen in the picture.
http://img219.imageshack.us/img219/3424/picnw3.th.jpg
charged with surface density \sigma(\theta)=\sigma_{0}cos\theta
Need to find the Electric field in center of the axis.
As I see the direction of the electric field is the Z axis...
A long tube charge with charged with uniform spatial density \rho.
The inner radius of the tube is: a
The outer radius of the tube is: b
Need to find the electric field in: a<r<b
My approach is Gauss:
E*S=4 \pi kq
The S is the Gaussean Surface it should be 2 \pi r^2 ??
and q should be...