Question

Prove that Cos²a + sin²a = 1

Answer 1

Step-by-step explanation:

Cos A = Base/Hypotenuse (B/H)

Sin A = Perpendicular/Hypotenuse (P/H)

By Pythagoras Theorem,

H^2 = P^2 + B^2 .......(1)

sin^2 A + cos^2 A

P^2/H^2 + B^2/H^2

(P^2 + B^2)/H^2

From (1),

H^2/H^2 = 1

Hence, Sin^2 A + Cos ^2 A = 1