Question

упростите: (sin a - cos a)^2 + (sin a + cos a)^2

Answer 1

sin²a - 2sinacosa + cos²a +sin²a + 2sinacosa + cos²a = 1 + 1 = 2

Answer 2

(sinx-cosx)²+(sinx+cosx)²=sin²x-2sinx*cosx+cos²x+sin²x+2sinx*cosx+cos²x=
2*sin²x+2*cos²x=2*(sin²x+cos²x)=2*1=2.