Question 353549
Let {{{u=a^3+x^3}}}
{{{y=cos(u)}}}
{{{dy/dx=(dy/du)*(du/dx)}}}
{{{dy/du=-sin(u)}}}
{{{du/dx=3x^2}}}
{{{dy/dx=-sin(u)*(3x^2)}}}
{{{dy/dx=-3x^2*sin(a^3+x^3)}}}