Question

anyone plzz tell
if you dont know dont answer wrong​

Answer 1

Sin∅+Cos∅=a

Sin∅-Cos∅=b

prove a²+b²=2

(Sin∅+Cos∅)²+(Sin∅-Cos∅)²=RHS

[use (a+b)²=a²+2ab+b² and (a-b)²=a²-2ab+b² equation]

Then,

Sin²∅+2.Sin∅.Cos∅+Cos²∅+Sin²∅-2.Sin∅.Cos∅+Cos²∅ = RHS

Rearrange it

Sin2∅+Cos²∅+Sin²∅+Cos²∅+2.Sin∅.Cos∅-2.Sin∅.Cos∅ = RHS

1+1+0 = RHS [Because Sin²∅+Cos²∅=1]

2=RHS