# Calc integration

1. Apr 25, 2005

### UrbanXrisis

question and work is here

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

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.