# Thread: Finding value of sin(theta) from value of cos(theta).

1. ## Finding value of sin(theta) from value of cos(theta).

I've been staring at this question...for so long.

if cos/theta = 1/3 , find the value of 6sin^2/theta - 6

2. Use the Pythagorean Identity:

$\displaystyle \sin^2{\theta} + \cos^2{\theta} = 1$.

Substitute $\displaystyle \cos{\theta}$ and then rearrange.

3. Thanks for the tip!!