When on a slope, why is the x-component sin and the y-component cos

In the problem I'm doing a car is on a 10 degree slope. When they are evaluating the x and y components in my textbook they say that Fx=-mgsin(theta)-fk=ma and that Fy=n-mgcos(theta)=ma(y).
I understand all of the other components in the equation except for why sin and cos are reversed...isn't sin suppoesd to be for the vertical component and x supposed to be for the horizontal (x) component? I'm confused

Thanks guys :)

".isn't sin suppoesd to be for the vertical component and x supposed to be for the horizontal (x) component?"

Get that kind of absolute reasoning out of your head. It is only true if you use strict discipline when defining the coordinate system of angles.



The deal is, cosine gets the component aligned with the REFERENCE RAY of the angle. Sine gets the component perpendicular to the reference ray of the angle.

Think about where you define your angle, and what is the limiting condition when the angle equals 0 or when the angle equals 90 degrees.