Chapter 14.2

Cosine graph: y = cos x

What You'll Learn

Identify cosine values using x-coordinates on the unit circle
Plot key points of the cosine function at critical angles (0°, 90°, 180°, 270°, 360°)
Recognize that cosine is a periodic function with period 2π
Compare cosine graph characteristics to sine graph (both have period 2π)
Understand that cosine starts at its maximum value of 1 when the angle is zero

What You'll Practice

1

Finding cosine values at standard angles using unit circle coordinates

2

Plotting cosine function points in both positive and negative directions

3

Connecting plotted points to sketch the complete cosine curve

4

Identifying period and repeating patterns in the cosine graph

Why This Matters

Understanding the cosine graph is essential for modeling periodic phenomena like sound waves, alternating currents, and oscillations in physics and engineering. This foundation prepares you for advanced trigonometry, calculus, and real-world applications in science and technology.

Before You Start — Make Sure You Can:

Use cosine ratio to calculate angles and sides (Cos = \( \frac{a}{h}\) )Unit circleConverting between degrees and radians

This Unit Includes

1 Video lesson

Skills

Cosine Function
Unit Circle
Trigonometric Graphs
Periodic Functions
Angle Measures
Coordinate System
Function Plotting
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