Homework Help: Integrate int (sin^2(t) + cos^2(t) -1)dt from e^x to e^(2x)

1. Mar 19, 2008

cooltee13

1. The problem statement, all variables and given/known data

Integrate from e^x to e^2x: (sin^2(t) + cos^2(t) -1)dt

2. Relevant equations
just standard integral equations

3. The attempt at a solution

I know how to do most of it, my only question is: is (sin^2(e^2x) + cos^2(e^x) -1) a special trig identity? or would i just solve it like a normal interation in parts problem?

2. Mar 19, 2008

sutupidmath

well it seems trivial to me... lol
This question seems to be just tricky, nothing else.

3. Mar 19, 2008

regor60

Aren't the sin and cos together adding to 1 the way you've written it, thus 1-1=0 ? You may want to double check you have it correct

4. Mar 19, 2008

sutupidmath

$$\int_{e^{x}}^{e^{2x}}(sin^{2}(t)+cos^{2}(t)-1)dt=\int_{e^{x}}^{e^{2x}}(1-1)dt=\int_{e^{x}}^{e^{2x}}(0)dt=?????$$

What does this equal to??

5. Mar 19, 2008

cooltee13

ok, thanks guys lol. I feel dumb now

6. Mar 19, 2008

sutupidmath

Ok, integrate the following:

$$\int_0^{ln(1)} sin(x)e^{-x^{2}}dx$$

This question was somewhere i dunno where though. Give a shot to it.

HINT: THis is also tricky.

Last edited: Mar 19, 2008
7. Mar 19, 2008

cooltee13

Isnt that just equal to 1?

8. Mar 19, 2008

rocomath

Look at your limits of Integration

From 0 to Ln(1)

9. Mar 19, 2008

sutupidmath

Why on earth do u think it is equal to 1?

10. Mar 19, 2008

sutupidmath

How did u change your display name?