# What is the relationship between sine and cosine?

Jul 3, 2015

Relationship between sin and cos

#### Explanation:

There are many of them. Here are a few:

1. They are the projections of an variable arc x on the 2 x-axis and y-axis of the trig circle.

2. Trig identity: sin^2 x + cos ^2 x = 1

3. Complementary arcs: $\sin \left(\frac{\pi}{2} - x\right) = \cos x$