Given that cos θ = frac{1}{9}, calculate the value of sin θ.

Question

anonymous · Answer

I am really stuck on this problem.

anonymous · Answer

so to solve sin, first you have to solve for cos

anonymous · Answer

there are 2 ways to do this, pythagorean or using calculators to find degrees.

anonymous · Answer

I'll show you both, choose one you like more?

anonymous · Answer

both

solomonzelman · Answer

1² + b² = 9²

sin = b / 9

amistre64 · Answer

sin^2 + cos^2 = 1  :)

anonymous · Answer

cos theta= 1/9

cos^-1 (1/9) = theta
theta = 83.62 degrees

sin 83.62= 0.9938

anonymous · Answer

and the second was solomon's way :D

anonymous · Answer

why do you square -1?

anonymous · Answer

a^2 + b^2 = c^2
pythagorean theorem

anonymous · Answer

so you do pythagorean theorem then sin

anonymous · Answer

on 2nd though pythagorean would not be applicable for every problems since we don't know if this is a right triangle or not.

anonymous · Answer

thought*

just use your calc to find cos and sin instead.

or you can use sin^2 + cos^2 = 1  , that one is always true

anonymous · Answer

ok thanks