Trigonometry Explained

Trigonometry Explained
Trigonometry Explained | Ideasthesia

Trigonometry isn't about triangles. It's about circles.

The triangle is just how the circle reveals itself when you freeze a moment of rotation. Sine, cosine, tangent — these aren't triangle measurements. They're coordinates of a point spinning around a center.

This changes everything about how trigonometry feels. Once you see the circle hiding inside every triangle, the subject transforms from memorizing ratios to understanding rotation.

What You'll Learn

This series covers the mathematics of circles hiding in triangles:

The Core Insight

Trigonometry is the mathematics of circular motion frozen at a moment in time. Every sine value, every cosine, every tangent comes from a point on a circle.

When you learn trigonometry this way, you're not memorizing formulas. You're learning to see the rotation hiding in everything that oscillates, cycles, or repeats.


This is the hub page for the Trigonometry series.

Next: What Is Trigonometry? The Mathematics of Circles Hiding in Triangles

The Series

What Is Trigonometry? The Mathematics of Circles Hiding in Triangles
Introduction to trigonometry - not triangle math but circle math in disguise
Sine Explained: The Height of a Point on a Spinning Circle
Sine is vertical position on the unit circle - why it oscillates and what that means
Cosine Explained: The Horizontal Partner to Sine
Cosine is horizontal position on the unit circle - sine shifted by 90 degrees
Tangent Explained: The Ratio That Measures Slope
Tangent is sine over cosine - the slope of the radius at any angle
The Unit Circle: Why Radius 1 Changes Everything
The unit circle makes trigonometry simple - radius 1 means coordinates are the trig values
The Law of Sines: Every Triangle Is a Circle Trying to Express Itself
The law of sines relates sides to opposite angles - triangles inscribed in circles
The Law of Cosines: Pythagoras Generalized for Any Triangle
The law of cosines extends Pythagoras to non-right triangles - what happens when angles are not 90
SOH CAH TOA: The Mnemonic That Hides the Meaning
SOH CAH TOA helps you remember but not understand - what the ratios actually mean
Trigonometric Identities: Why sin²θ + cos²θ = 1 Had to Be True
Trig identities are not arbitrary - they follow from the geometry of the circle
Radians vs Degrees: Why Mathematicians Prefer Radians
Radians measure arc length directly - why π appears everywhere in higher math
Waves and Oscillation: Why Sine Shows Up Everywhere
Sine describes any smooth oscillation - pendulums sound light and quantum mechanics
Synthesis: Trigonometry as the Language of Cycles
Trigonometry is how the universe writes repetition - from orbits to heartbeats