Given that theta is in quadrant II and tan theta 87 find co

Given that theta is in quadrant II and tan theta = -8/7 find cos theta.

Solution

tan theta= -8/7

theta is in second quadrant , and in second quadrant cosine is negative

Here opposite= 8 and adjacent=7

hypotenuse = sqrt(8²+7²)= sqrt 113

cos theta= adjacent / hypotenuse =- 7/sqrt113= -7sqrt113/113