Question

The point (3, -4) is on the terminal side of an angle 0 . What is cos 0  ?

Answer 1

draw it
cos=oposite side/hypothuse

oposite side=y=-4
hypotonuse=distance from (0,0) to (3,-4)
which is $D=\sqrt{3^2+(-4)^2}=\sqrt{9+16}=\sqrt{25}=5$

so it would be -4/5