Question

s. Prove that; sin^2+cos^2 =1 .

Answer 1

Step-by-step explanation:

To prove :- sin^2A + cos^2A = 1

Proof :-

Let ABC be a right angled ∆ , right angled at B and <C = theta

We have ,

sin theta = AB/AC

cos theta = BC/AC

Now , sin^2theta + cos^2theta = (AB/AC)^2 +( BC/AC)^2

= (AB^2+ BC^2)/AC^2

= AC^2/AC^2 {using Pythagoras theorem}

= 1

Hence , proved