Answer
$y=p(14k^3-12k^2)=7.9 \sin (14k^3-12k^2)$
$\frac{d( p(14k^3-12k^2) )}{dk}= 7.9 \cos (14k^3-12k^2) (42k^2-24k)$
Work Step by Step
$p(t)=7.9\sin t$
$t(k)=14k^3-12k^2$
$y=p(14k^3-12k^2)=7.9 \sin (14k^3-12k^2)$
Taking derivative with respect to $k$
$\frac{dy}{dk}= 7.9 \cos (14k^3-12k^2) \frac{d(14k^3-12k^2)}{dk}$
$\frac{d ( p(14k^3-12k^2) )}{dk}= 7.9 \cos (14k^3-12k^2) (42k^2-24k)$
