The slope of the given equation is
Where A = 2, and B = 1.
But, the slope is equal to the tangent function:
If we consider this tangent function about a right triangle, then the opposite leg is 2, and the adjacent leg is 1. Using Pythagorean's Theorem, we find the hypothenuse.
So, the sine function is
And, the cosine function is
The inverses are