Question

Вычислить производную функции y=2cos2x+cos4x
A 8sinxsin3x
B -8cosxsin3x
C 8coscxcos3x
D 8sinxcos3x

Answer 1

1. y'= -4sin2x-4sin4x= -4(sin2x+sin4x)= -8sin3xcosx.
2. B: -8cosxsin3x

Answer 2

$y=2cos2x+cos4x \\ y'=-4sin2x-4sin4x$