Library/Algebra/Trigonometry/Trigonometric inequalities

Trigonometric inequalities

Overview
Important

A trigonometric inequality is an inequality that involves trigonometric functions such as sinx\sin x, cosx\cos x, or tanx\tan x. To solve these, we find all values of xx (usually in a given interval) that make the inequality true.

Important properties

  • Trigonometric functions are periodic, so solutions often repeat at regular intervals.

  • The range of sinx\sin x and cosx\cos x is [1,1][-1, 1], which limits possible solutions.

  • Inequalities may require considering the sign of the trigonometric function in different intervals.

  • Graphical methods can help visualize where the inequality holds.