(cos(b+15)-cosb*cos15) / sinb*cos15

Question

(cos(b+15)-cosb*cos15) / sinb*cos15

Comments

разложи первую фигню по формуле cos(x+y)=cosxcoy-sinxsiny

Answer 1

(cosb*cos15-sinb*sin15-cosb*cos15)/(sinb*cos15)=(-sinb*sin15)/(sinb*cos15)=-sin15/cos15=-tg15

Comments

да так