Question

упростите cos(п+2a)+sin(п+2a)*tg(п/2+a)

Answer 1

$cos( pi +2 alpha )+sin( pi +2 alpha )cdot tg( frac{ pi }{2} + alpha )= \ =- cos alpha -sin2 alpha cdot (-ctg alpha )=- cos alpha +sin alpha cdot cos alpha cdot ( frac{cos alpha }{sin alpha } )= \ =cos^{2} alpha -cos alpha$