Question

Angle 0 lies in the second quadrant and sin 0 = 3/5 cos= coy =

Answer 1

Consider the right triangle ABC with legs AB=4, AC=3 and hypotenuse BC=5. Angle B has

`\sin B=(opposite)/(hypotenuse) = (3)/(5)` and

`\cos B = (adjacent)/(hypotenuse) = (4)/(5)`.

Since O lies in second quadrant
`\cos O\ \textless \ 0` and

`\cos O= -\cos B =- (4)/(5)`.
Answer:
`\cos O=- (4)/(5)`.