please help me

[canada]

i have some guestions which i can not answer, if someone gives me a hand, i will be very glad.

a) d sec (x²-4)
dx

b)d³tan x
dx³

c)d , x sin x+x²
dt x²+1

d) f ‘’ (x) if (x)= sec(4x)

 

[royhaas]

All use the chain rule in one form or another. For b) it will be a little messy. For c) use dy/dt = (dy/dx)(dx/dt)