Recent content by kensaurus

1. Finding expectation and variance

So for example, if I have a random variable X, take it to be normally distributed. How do you find the expectation and variance of the random variable e^X in terms of μ and σ? Integrating the entire normal function with the f(x) is it?
2. Exponential Generating Functions

oh my, im slapping my head... i went to derive it through complex, exponential functions and other means... thanks alot!
3. Exponential Generating Functions

I got a question here, and I am stuck at understanding the step of the solution. Any help will be appreciated. http://img841.imageshack.us/img841/6589/40155869.jpg [Broken] I would like to know how to get from the second to the third step, where the summation comes in. It looks like...
4. Area bounded inside the quarter-circles.

yes it is brilliant indeed! found an exhaustive explanation here too :) http://uk.answers.yahoo.com/question/index?qid=20100609093348AAFVp5w
5. Area bounded inside the quarter-circles.

so it all comes down to integration? okay, thanks... btw, this was a question from mensa, so i think there should be a brilliant way to solve it -.-
6. Area bounded inside the quarter-circles.

i just realized that the equations cant be solved based on your equations. it still results in 2 equations and I AM UNABLE to find your third equation. any help please?
7. Area bounded inside the quarter-circles.

Its a question that I had from a friend in the past. I had tried solving it but to no avail. Have tried integration and stuff like that, but I think there is an easier way to solve this question. Question -> Square of 7cm, find the shaded area...
8. Tunneling through a PE barrier

dont understand what is Ibrits talking about... too complex -.-" What do you mean by kinetic energy is an operator acting on a wavefunction" and "wavefunction is a growing or (usually) decaying, instead of oscillating"?