## anonymous 3 years ago Use trig identites to transform the left side of equation into the right. (1+cos theta)(1-cos theta)= sin^2theta

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1. AravindG

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

2. anonymous

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. anonymous

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

5. anonymous

ooohh. yea. I see.

6. anonymous

kk good

7. anonymous

thank you(:

8. anonymous

yw

9. goformit100

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10. anonymous

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

11. anonymous

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