What is the derivative of this function y=(cos1(4x2))2?

1 Answer
Aug 4, 2017

ddx(arccos(4x2))=16xarccos(4x2)116x4.

Explanation:

Note that ddx(arccos(x))=11x2.

Then, by the chain rule
ddx(arccos(4x2))=2(arccos(4x2))ddx(arccos(4x2)).

Then, by the chain rule again,
ddx(arccos(4x2))=1116x4ddx(4x2),
ddx(arccos(4x2))=8x116x4.

Substituting,

ddx(arccos(4x2))=16xarccos(4x2)116x4.