This example has a function of a function of a function.

Let `u = 2x` and `v = cos\ 2x`

So we can write `y = v^3` and `v = cos\ u`

` {: ((dy)/(dx),=(dy)/(dv)(dv)/(du)(du)/(dx)),(,=3v^2(-sin\ u)(2)),(,=3(cos^2 2x)(-sin\ 2x)(2)),(,=-6\ cos^2 2x\ sin\ 2x) :}`