Course: Trigonometry
Topic: Graphs of Trigonometric Functions
Subtopic: Amplitude & Period


Altering a trigonometric function by multiplying it by a constant changes its graph by stretching it taller or squishing it flatter. This is called a change in amplitude. Altering it by multiplying its angle by a constant changes its graph by stretching / squishing it like a spring. This is called a change in period. In this lesson we learn the effect of these changes on the six trig functions.


By the end of this topic you should know and be prepared to be tested on:


Terms you should be able to define: amplitude, period (of a trig function), periodic

Text Notes

You may SKIP any "curve fitting" and "regression" examples/problems in this section and throughout the course including "sine regression".

Mini-Lectures and Examples

STUDY: Graphs - 6 Trig Functions, Amplitude, Period

Supplementary Resources (recommended)

Explore how changing the "a" (amplitude) and "b" (period) values on the slider bar affect the sine graph at Sine Amplitude and Period from Desmos.

Supplemental Resources (optional)

Video: Amplitude and Period of Sine and Cosine

rev. 2020-10-19