tg23*tg293+sin52*sin128-sin322*sin142

tg23*tg(270+23)+sin52*sin(180-52)-sin(360-38)*sin(180-38)=-1+1=0tg23*tg293=sin293sin23/cos293cos23==1/2*(cos270-cos316))/[1/2*(cos270+cos316)]=-cos316/cos316=-1sin52*sin52-(-sin38)*sin38=sin²52+sin²38=sin²(90-38)+sin²38=cos²38+sin²38=1