# Thread: Find the cumulative and probability density functions

1. ## Find the cumulative and probability density functions

Anyone know how I can get this question started?

What does the 'max' function mean?

2. max means maximum or largest of the three

$P(Y\le x)=P(X_1\le x, X_2\le x, X_3\le x)$

use independence.....

$=P(X_1\le x)P(X_2\le x)P(X_3\le x)$

now use your distribution function for the exponential.

3. Originally Posted by My Little Pony
Anyone know how I can get this question started?

What does the 'max' function mean?
Use Google to research Order Statistics (you will also find many relevant threads in this subforum using the Search tool).

4. I got:

(1 - exp(-theta*x))^3 as the cdf and 3*theta*exp(-theta*x)*(1 - exp(-theta*x) as the pdf.

Can someone verify if this is correct?