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# need some brief clarification on cumulative and probability functions (s2) Watch

1. if you are given a pdf (e.g. f(x): k(y^3 + y^2) for 1<=y<=2) and asked to show that k = 20 (random number, probably doesnt work)

you would integrate with limits 1 and 2 and equate it to 1, correct?

now if you are given a cdf and asked to show that k = a specific number. would you just substitute the max limit in and equate it to 1? e.g.

F(x): k(y^3 + y^2) for 1<=y<=2
F(2): k(2^3 + 2^2) = 1

i'm really confused, can anybody just clear this up for me? would be much appreciated, thanks

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Updated: December 25, 2010
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