# Math Help - Kindly help about Probability density function

1. ## Kindly help about Probability density function

Consider a signal having probability density function p(f) equals to
K exp(-|f|) for -4<f<4 and zero otherwise.

Kindly find value of K

2. It's an even function, so you don't need two integrals.

$.5=k\int_0^4e^{-x}dx=k\bigl(1-e^{-4}\bigr)$

3. ## i think it should be other way round

Thanks a lot
i think it should be like this

0.5 = K [exp(-4) -1]

What u say

4. Originally Posted by moonnightingale
Thanks a lot
i think it should be like this

0.5 = K [exp(-4) -1]

What u say

NOPE

1 look over the chain rule
2 densities must be nonnegative, try calculating your k, with the math you think is correct

The derivative and hence integral of $e^{-x}$ is $-e^{-x}$