Question

If sin o = 2/3 and tan < 0 what is the valuse of cos 0​

Answer 1

-(√5)/3

Explanation:

The tangent being negative means the sine and cosine have opposite signs. Using the identity ...

cos(o) = ±√(1 -sin(o)^2)

we find ...

cos(o) = -√(1 -(2/3)^2) = -√(5/9)

cos(o) = -(√5)/3