## Trigonometry

The topic of trigonometry cannot escape GP. In fact, it forms the backbone of the whole GP. Let’s go through some of the bacis: sine, cosine and tangent.

Here’s a diagram that will sum them up:

Note that these basics are used to translate polar coordinate to Cartesian coordinate. Recall polar coordinate is written as (magnitude, angle) while Cartesian coordinate is (x, y). For example write in Cartesian coordinate format the polar coordinate (10, 30).

So there you have it. Another important application of trig is to quickly obtain the angle of triangle given sides x and y. Check out image below.

This case happens when you want to do the reverse: translating from Cartesian to polar. Given Cartesian coordinate (x1, y1) measured __origin__, we shall use the Pythagoras’ theorem to get the magnitude and inverse tangent of side y over x to get angle.