Algebra · Graphs of functions
Chapter 1 · 4
The idea
Trigonometric graphs
The sine and cosine waves from 0° to 360° — where they start, peak and cross — why they never leave the band −1 to 1, and how wave symmetry finds the second solution of sin x = k.
A full journey — read it, play with it, work it, then earn real exam marks. Everything stays on the timeline below.
In this lesson — start anywhere
Algebra · Graphs of functions
Trigonometric graphs
The sine and cosine waves from 0° to 360° — where they start, peak and cross — why they never leave the band −1 to 1, and how wave symmetry finds the second solution of sin x = k.
Why it works
Two waves in a band
Work out for every angle from round to and plot the lot, and a shape appears that runs through tides, sound and daylight hours: a wave. Sine and cosine both make one — they repeat every and stay forever in the band between and . Those two facts, plus where each wave starts, are the whole topic.The sine wave, 0° to 360°
starts at , climbs to its peak at , comes back to at , dips to at , and returns to at . Crossings at .Keep reading — free
The rest of the explanation, plus 2 worked examples you step through move by move.
Start freeTakes a minute — no card.