## my-geek-pride 2 years ago Use trig identites to transform the left side of equation into the right. (1+cos theta)(1-cos theta)= sin^2theta

• This Question is Open
1. AravindG

1+cos theta =2cos^2 theta/2

2. satellite73

multiply on the left, and get $1-\cos^2(\theta)$ then it should be easy enough

3. AravindG

1-cos theta=2sin^2 theta/2

4. satellite73

is it clear that $1-\cos^2(\theta)=\sin^2(\theta)$?

5. my-geek-pride

ooohh. yea. I see.

6. satellite73

kk good

7. my-geek-pride

thank you(:

8. satellite73

yw

9. goformit100

"Welcome to OpenStudy. I can guide regarding this useful site; ask your doubts from me, for it you can message me. Please use the chat for off topic questions. And remember to give the helper a medal, by clicking on "Best Answer". We follow a code of conduct, ( http://openstudy.com/code-of-conduct ). Please take a moment to read it."

use identity ---> a^2 - b^2 for lhs then prove using cos2 + sin2 = 1

11. mjithin

(1+cosθ)(1−cosθ)=(1−cosθ+cosθ−cos2θ) = sin2theta