Question

the value of (sintetta+costetta)² +(sintetta-costetta)​

Answer 1

Correct Questions

=> ( Sinθ + Cosθ )² + ( Sinθ - Cosθ )²

Solution

We have

=> ( Sinθ + Cosθ )² + ( Sinθ - Cosθ )²

Using This Identities

=> ( a + b )² = a² + b² + 2ab

=> ( a - b )² = a² + b² - 2ab

We get

=> Sin²θ + Cos²θ + 2SinθCosθ + Sin²θ + Cos²θ - 2SinθCosθ

We Know That

=> Sin²θ + Cos²θ = 1

We get

=> 1 + 2SinθCosθ + 1 - 2SinθCosθ

=> 1 + 1 + 0

=> 2

Answer

=> 2