Question

(Seno+coseno)^2 + (seno-coseno)^2=2

Answer 1

(senx + cosx)² + (senx - cosx)² = 2

(sen²x + 2senxcosx + cos²x) + (sen²x - 2senxcosx + cos²x) = 2

(sen²x + cos²x) + (sen²x + cos²x) + ( 2senxcosx - 2senxcosx) = 2

1 + 1 + 0 = 2

2 = 2