Explanation: Before we begin, remember that: tan α =
Now for the given, we have: cos θ - tan θ * cos θ = 0 cos θ - * cos θ = 0 cos θ - sin θ = 0cos θ = sin θ Now, divide both sides by cos θ, we get: 1 = tan θ
Following the ASTC rule, we know that the tan function is positive in the first and third quadrants. This means that: either θ =