Question

Преобразовать выражение (2сos^2(68)-1)/(2cos(113)*sin(67))

Answer 1

(2сos²(68)-1)/(2cos(113)*sin(67))=сos136/2cos(180-67)sin67=
=cos136/(-2cos67sin67)=-cos136/sin134=-cos(90+46)/sin(180-46)=sin46/sin46=1