Question

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

Answer 1

I am really stuck on this problem.

Answer 2

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

Answer 3

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

Answer 4

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

Answer 5

both

Answer 6

1² + b² = 9²

sin = b / 9

Answer 7

sin^2 + cos^2 = 1 :)

Answer 8

cos theta= 1/9

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

sin 83.62= 0.9938

Answer 9

and the second was solomon's way :D

Answer 10

why do you square -1?

Answer 11

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

Answer 12

so you do pythagorean theorem then sin

Answer 13

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

Answer 14

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

Answer 15

ok thanks