Question

sin(90+альфа)-cos^2(альфа-90)/sin(альфа+270) 10 класс

Answer 1

$sin(90+ alpha ) - frac{cos^{2} ( alpha -90) }{sin( alpha+270)} =sin(90+ alpha ) - frac{cos^{2} ( 90-alpha ) }{-sin( 90-alpha)} =cos alpha+ frac{sinalpha}{cosalpha} = cos alpha+tg alpha$