Question

If cosine of x equals (-4/5) and tan of x is greater than 0, the value of sine x is???

Answer 1

`3^2+4^2=5^2.` Negative cosine and positive tangent means negative sine, so

`sin x = pm sqrt{1 - cos^2x } = - sqrt{1 - (-4/5)^2} = -3/5`