A trigonometric inequality is an inequality in which the unknown appears as the argument of trigonometric functions. The general method is always the same: reduce the inequality to a product of elementary factors, study the sign of each factor on the unit circle (or on the graph), combine the signs in a table and read the solution. The chapter starts from the elementary inequalities with sin\sin, cos\cos and tan\tan, read directly on the circle; it then moves on to the sign-study method for inequalities that can be factorised; and finally it recalls, on trigonometric ground, the techniques already seen for the absolute value and for roots.

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Exercises