Question

упростить выражение: sin*a cos*a ctg*a

Answer 1

sin(a)*cos(a)*ctg(a)=cos(a), т.к. ctg(a)=cos(a)/sin(a)

Answer 2

sin(a)*cos(a)*ctg(a)=sin(a)*cos(a)*(cos(a)/sin(a))=(sin(a)*cos(a)*(cos(a))/sin(a)=(cos(a))^2