A curve C has equation
y=3sin2x+4cos2x,
The point A(0, 4) lies on C.
(a) Find an equation of the normal to the curve C at A
when i defferintiate i got this dy/dx= 6cos2x - 8sin2x
my problem was when i subsituted the x=0 i had the wrong value of the gradient
in the MS m=6
show your working