Pythagorean Identity

Question

Am I suppose to plug in the fraction for cos into the equation above and find the other fraction to make it equal to 1 or is there more to this problem? Can someone please explain ()

Answer 1

Hint - you can derive formulas.

Formula 1 -

$\sin^2 \theta = 1 - \cos^2\theta$

$\sin \theta = \sqrt{1 - \cos^2\theta}$

Formula 2 -

$\cos^2 \theta = 1 - \sin^2\theta$

$\cos\theta = \sqrt{1 - \sin^2\theta}$

In your question you need formula 1.

Answer 2

Directly from the equations you have $\sin\theta=\sqrt{(1-\cos^{2}\theta)}$. You can do the rest.