Given the inequality: cot(x)≥3 To solve this inequality, we must first solve the corresponding equation: cot(x)=3 Solve: Given the equation cot(x)=3 transform cot(x)−3−1=0 cot(x)−3−1=0 Do replacement w=cot(x) Expand brackets in the left part
-1 + w - sqrt3 = 0
Move free summands (without w) from left part to right part, we given: w−3=1 Divide both parts of the equation by (w - sqrt(3))/w
w = 1 / ((w - sqrt(3))/w)
We get the answer: w = 1 + sqrt(3) do backward replacement cot(x)=w substitute w: x1=6π x1=6π This roots x1=6π 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 = −101+6π = −101+6π substitute to the expression cot(x)≥3 cot(−101+6π)≥3