Question

упростить (sinx+cosx)^2+(sinx-cosx)^2;
cos^2x/1-sinx-sinx

Answer 1

$(sin x+cos x)^2+(sin x+cos x)^2=\ =sin^2 x+2sin x cos x+cos^2x+sin^2 x-2sin x cos x+cos^2 x=\ =sin^2x+cos^2x+sin^2 x+cos^2x=1+1=2$


$frac{cos^2 x}{1-sinx}-sin x= frac{cos^2x-sin x+sin^2 x}{1-sin x} = frac{1-sinx}{1-sin x} =1$

Answer 2

1) sin^2x+2*sinx*cosx+cos^2x+sin^2x-2*sinx*cosx+cos^2x=1+1=2
Там по формуле (a+b)^2 и (a-b)^2