# integration with trig functions

• May 6th 2006, 04:38 PM
cinder
integration with trig functions
What is the integrated form of $\int4cos(5x)dx$ and $\int\frac{4}{cos^2x}dx$?

The answers I got are $\frac{4}{5}sin(5x)+C$ and $4tanx+C$, respectively.
• May 6th 2006, 06:24 PM
AfterShock
Are you wanting the process of finding those, or are you just checking to see if the answers are correct? You could just check by differentiating; if you do, you will notice that those are the correct answers.
• May 6th 2006, 06:33 PM
cinder
I thought they were correct, but I'm looking at an old calculus exam of mine and they are marked wrong. :confused:

I guess I should have said something earlier. Thanks.
• May 6th 2006, 06:50 PM
ThePerfectHacker
Quote:

Originally Posted by cinder
I thought they were correct, but I'm looking at an old calculus exam of mine and they are marked wrong. :confused:

I guess I should have said something earlier. Thanks.

Maybe you did the oldest mistake in the book, you forgot the constant at the end?

This is may 1:):):)th Post
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