Question

prove that $sin^{2}a+cos^{2}a=1$​

Answer 1

Answer:

solved

Step-by-step explanation:

by drawing a right angle triangle with unit hypotenuse , the other sides

will be

opposite of angle a = sina

adjacent of angle a = cosa

now applying the phithagorian  theorem , we get

sin²a + cos²a = 1

Answer 2

Answer:

sin²a + cos²a = 1

sin²a = 1 - cos²a

cos²a = 1 - sin²a

Let ∆ABC is a right angled ∆le and

right angle at angle B

let angle A = a

Now

Sin a = opp / adj = BC / AC

Cos a = adj / hyp = AB / AC

Now , RHS

sin² a + cos² a = [BC/AC]² + [AB/AC]²

[ By Pythagoras theorem AC² = AB²+BC²]

===> BC² / AC² + AB² / AC²

===> BC² + AB² / AC²

===> AC² / AC²

===> 1

Sin²a + Cos²a = 1

Hence proved .