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# s2 continuous random variable watch

1. i can usually do these type of questions but this one has baffled me.

the random variable x has probability density function f(x)=(3x^k, 0<x<1)
Where k is a positive integer, find the value of k.
I just cant seem to get the correct answer
i have intergrated it and equalled it to 1 and then tried to rearrange it but i dont get the correct answer. Can someone show me some steps to do it
2. integrating

gives

if you set the limit between 1 and 0 and make it equal to 1 then

1 to any real number is 1. 0 to any real number (except 0) is 0. therefore:

and you can solve that.
3. Can you show your working? Either you have a silly error somewhere for which you will kick yourself, or the book is wrong.
Spoiler:
Show
(I got 2)

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Updated: January 13, 2010
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