Answer:
see explanation
Step-by-step explanation:
Using the Pythagorean identity
sin²θ + cos²θ = 1 ( divide terms by sin²θ )
[tex]\frac{sin^20}{sin^20}[/tex] + [tex]\frac{cos^20}{sin^20}[/tex] = [tex]\frac{1}{sin^20}[/tex] , that is
1 + cot²θ = cosec²θ ← as required