Given the inequality: tan(x)≥3 To solve this inequality, we must first solve the corresponding equation: tan(x)=3 Solve: Given the equation tan(x)=3 - this is the simplest trigonometric equation This equation is transformed to x=πn+atan(3) Or x=πn+3π , where n - is a integer x1=πn+3π x1=πn+3π This roots x1=πn+3π is the points with change the sign of the inequality expression. First define with the sign to the leftmost point: x0≤x1 For example, let's take the point x0=x1−101 = (πn+3π)+−101 = πn−101+3π substitute to the expression tan(x)≥3 tan(πn−101+3π)≥3