Question

найдите производную функции f x = 0,5 x * cos 2 x

Answer 1

$f(x)=0,5xcdot cos2x= \ f`(x)=(0,5xcdot cos2x)`=0.5(xcdot cos2x)`= \ =0.5(x`cdot cos2x+xcdot (cos2x)`)=0.5(cos2x-2xcdot sin2x)$