What is the derivative of #tan^7(x^2)#?

1 Answer
Aug 14, 2017

#d/(dx) [tan^7(x^2)] = color(blue)(14xtan^6(x^2)sec^2(x^2)#

Explanation:

We're asked to find the derivative

#d/(dx) [tan^7(x^2)]#

We can first use the chain rule:

#d/(dx) [tan^7(x^2)] = d/(du) [u^7] (du)/(dx)#

where

  • #u = tan(x^2)#

  • #d/(du) [u^7] = 7u^6#:

#= 7d/(dx)[tan(x^2)]tan^6(x^2)#

Using the chain rule again:

#d/(dx) [tan(x^2)] = d/(du) [tanu] (du)/(dx)#

where

  • #u = x^2#

  • #d/(du) [tanu] = sec^2u#:

#= 7d/(dx)[x^2]sec^2(x^2)tan^6(x^2)#

Use the power rule on the #x^2# term:

#d/(dx) [x^n] = nx^(n-1)#

where

  • #n = 2#:

#= 7(2x)sec^2(x^2)tan^6(x^2)#

#color(blue)(ulbar(|stackrel(" ")(" "= 14xsec^2(x^2)tan^6(x^2)" ")|)#