Recent content by kensaurus

  1. K

    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. K

    Exponential Generating Functions

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

    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. K

    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. K

    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. K

    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. K

    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. K

    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"?
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