Explanation:
Hey there!
The Pythagorean identity is: sin²(theta) + cos²(theta) = 1.
So, For finding sin (theta);
Take cos (theta) right side.
sin²(theta) = 1-cos²(theta)
Now, take square on right side from.
sin (theta) = √[1-cos²(theta)] {square changes into square root}
Therefore, sin (theta) = √[1-cos²(theta)].
Hope it helps!