Question

Найти производную от
cos(x) * cos (3x) - sin (x) * sin (3x)

Answer 1

(cos(x) * cos (3x) - sin (x) * sin (3x))' = (-sin(x) * cos(3x) - 3x * sin(3x) * cos(x)) - (cos(x) * sin(3x) + 3x * cos(3x) * cos(x))

Answer 2

(-sinx*cos3x-3sin3x*cosx)-(cosx*sin3x+3cosx*sinx)