# Thread: Some help with evaluating integrals

1. ## Some help with evaluating integrals

There are some problems that are confusing me when it comes to evaluating integrals:

http://www.webassign.net/www21/symIm...3accf0390f.gif

so obviously..the antiderivative of the denominator is the inverse sine of x but..and then the whole thing would be 9x/sin-1x?
if that's so then I keep getting the wrong answer. What am I doing wrong?

and how would i find the derivative of this function: http://www.webassign.net/www22/symIm...2415e68a78.gif

this one confused me a lot.

i'll take all the help i can get! thank you so much in advance

2. Originally Posted by mnm1390
There are some problems that are confusing me when it comes to evaluating integrals:

http://www.webassign.net/www21/symIm...3accf0390f.gif

so obviously..the antiderivative of the denominator is the inverse sine of x but..and then the whole thing would be 9x/sin-1x?
if that's so then I keep getting the wrong answer. What am I doing wrong?
the antiderivative is 9arcsin(t), not 9/arcsin(t).

and how would i find the derivative of this function: http://www.webassign.net/www22/symIm...2415e68a78.gif

this one confused me a lot.
FTC ... $\frac{d}{dx} \int_a^u f(t) \, dt = f(u) \cdot \frac{du}{dx}$