A counterexample for the expression secФ / tanФ = sinФ is 45°
This is a FALSE statement.
Explanation:
Solving Right-hand side:
SecФ = 1 / CosФ
tanФ = SinФ / CosФ
secФ/tanФ = 1 / CosФ ÷ SinФ / CosФ
secФ/tanФ = 1 / CosФ × CosФ/SinФ
secФ/tanФ = CosФ / SinФCosФ
secФ/tanФ = 1 / SinФ
Hence,
Left-hand side ≠ Right-hand side
