cos(π+2a)+sin(π+2a)*tg(π/2+a)=-cos2a-sin2a*(-ctga)=-cos2a+2sinacosa* cosa/sina=
=-cos^2a+sin^2a+2cos^2a=sin^2a+cos^2a=1
cos(π+2a)+sin(π+2a)*tg(π/2+a)=-cos2a-sin2a*(-ctga)=-cos2a+2sinacosa* cosa/sina=
=-cos^2a+sin^2a+2cos^2a=sin^2a+cos^2a=1