# What is the derivative of #y=sec^3(x)#?

##### 1 Answer

Aug 6, 2014

Thus,

And, we know that this is equivalent to

So, all we need to do is use the power rule, keeping in mind to use the chain rule on

#dy/dx = -3*(cos x)^(-4) * d/dx[cos x]#

#= -3*(cos x)^(-4) * (-sinx)#

#= 3sinx(cos x)^(-4) #

#= (3sinx)/(cos^4 x) #