# Thread: A general power formula question

1. ## A general power formula question

Hi. I worked this question many times.

28-2-20

(int)2 sqrt(1 - (e^(-x))) ((e^(-x)) dx)

General Power Formula:
u^(n+1) / (n + 1) = u^n du

Attempt:
u = (1 - e^(-x))
n = 1/2
du = -e^(-x) * - 1
du = e^(-x)

= (1 - e^(-x))^(1/2) / (3/2)

Pretty sure this is the wrong direction though, as the answer according to the Ti-89 is much more elaborate

2. ## Re: A general power formula question

Originally Posted by togo
Hi. I worked this question many times.

28-2-20

(int)2 sqrt(1 - (e^(-x))) ((e^(-x)) dx)

Is it $\int {2{e^{ - x}}\sqrt {1 - {e^{ - x}}} dx} ~?$

If it is what is the derivative of $\frac{4}{3}\sqrt {{{\left( {1 - {e^{ - x}}} \right)}^3}} ~?$

3. ## Re: A general power formula question

Hi togo. Please improve your post — it doesn't contain any question and it doesn't say what you are trying to do, so it's a little hard to help you.