Question

Find f''(x) if \[f(x)= 4(x^2+16)^{2/3}\]

Answer 1

\[y= 4(x^2+16)^{2/3} \\~\\\implies y^3 = 64(x^2+16)^2 \]

Now try differentiating implicitly

Answer 2

I got this answer:\[16x^2+256/3\]
and the real answer is this:
\[\frac{ 16(x^2+48) }{ 9(x+16)^3\sqrt{x^2+16} }\]