1) sin^2 (x)+sin2x=1 2) cos^2 (x) — sin2x=1

sin^2x+sin2x=1sin^2x+2sinx*cosx=1sin^2x+2sinxcosx=sin^2x+cos^2x2sinxcosx=cos^2x delim na cos^2x2tgx=1tgx=1/2x=arctg1/2+pi*kcos^2x-2sinx*cosx=sin^2x+cos^2x-2sinx*cosx=sin^2x'ctgx=-1/2x=-arcctg1/2+pi*n