# What are the first two derivatives of y = 2sin(3x) - 5sin(6x)?

y'=2×3cos(3x)-5×6cos(6x)=
$= 6 \cos \left(3 x\right) - 30 \cos \left(6 x\right)$
y''=-6×3sin(3x)+6×30sin(6x)=
$= - 18 \sin \left(3 x\right) + 180 \sin \left(6 x\right)$