Part 1/5:
An Introduction to Basic Trigonometry
Trigonometry, a branch of mathematics, is essential in understanding relationships involving angles and sides of triangles. This article presents some fundamental trigonometric concepts, specifically focusing on sine and cosine functions, and explores their relationship through graphical and algebraic proofs.
Understanding Sine and Cosine
The fundamental identities of sine and cosine include two key observations:
- The cosine of an angle plus (2\pi) (or 360 degrees) equals the cosine of the angle itself, which can be expressed as:
[
\cos(\theta + 2\pi) = \cos(\theta)
]
- Similarly, the sine of an angle plus (2\pi) equals the sine of the angle itself:
[
\sin(\theta + 2\pi) = \sin(\theta)
]