What is cos theta if (12, -5) is a point on the terminal side of theta?

1 Answer
Apr 18, 2017

cos(theta) = 12/13

Explanation:

The terminal arm should form the hypotenuse side of a right triangle such that 12^2 + (-5)^2 = c^2 = 169; that is c=13 , the hypotenuse side. a=12, the adjacent side, and b=-5 , the opposite side.
cos (theta) = (adjacent)/(hypoten\use) = 12/13