we are given
(x,y)=(5,-12)
so, x=5 and y=-12
now, we can find r
[tex] r=\sqrt{x^2+y^2} [/tex]
[tex] r=\sqrt{5^2+(-12)^2} [/tex]
[tex] r=13 [/tex]
now, we can find cos
[tex] cos(\theta)=\frac{x}{r} [/tex]
so, we get
[tex] cos(\theta)=\frac{5}{13} [/tex]...........Answer