Homework Help: Calc integration

1. Apr 25, 2005

UrbanXrisis

question and work is http://home.earthlink.net/~urban-xrisis/clip_image002.jpg [Broken]

I got the answer down to letter A and D. Now I feel like it's letter A but not sure...

Last edited by a moderator: May 2, 2017
2. Apr 25, 2005

whozum

Youre asking if $$\frac{sin^2(x)}{2} = \frac{-cos(2x)}{4}$$

Try x = 0

Or notice that f(x) = sin(x)cos(x) = sin(2x)/2, then the integral is real easy.

3. Apr 25, 2005

dextercioby

The easiest method is to differentiate each of the 3 results...

Daniel.

4. Apr 25, 2005

Knavish

Take the derivative of each of the choices.

*Haha, too late

5. Apr 25, 2005

Data

Not at all. If F(x) is an antiderivative of f(x) then so is F(x)+C for any C. Here,

$$\frac{\sin^2 x}{2} = \left(-\frac{\cos 2x}{4}\right) + \frac{1}{4}$$

Last edited: Apr 25, 2005
6. Apr 25, 2005

UrbanXrisis

how did you get III to be true?

7. Apr 25, 2005

Data

look at my last post.

8. Apr 25, 2005

whozum

Convert f(x) to what I recommended and the integral evaluates to D directly.

9. Apr 25, 2005

whozum

Good call, I didnt see that.