Use implicit differentiation where LaTeX:  \displaystyle y is a function of LaTeX:  \displaystyle x to find the derivative of LaTeX:  \displaystyle - 14 \sqrt{x} \sin{\left(y^{3} \right)} - 14 \sqrt{y} \cos{\left(x^{3} \right)}=3

Taking the derivative of both sides using implicit differentiation gives: LaTeX:   - 42 \sqrt{x} y^{2} y' \cos{\left(y^{3} \right)} + 42 x^{2} \sqrt{y} \sin{\left(x^{3} \right)} - \frac{7 y' \cos{\left(x^{3} \right)}}{\sqrt{y}} - \frac{7 \sin{\left(y^{3} \right)}}{\sqrt{x}} = 0  Solving for LaTeX:  \displaystyle y' gives LaTeX:  \displaystyle y' = \frac{6 x^{\frac{5}{2}} y \sin{\left(x^{3} \right)} - \sqrt{y} \sin{\left(y^{3} \right)}}{\sqrt{x} \cos{\left(x^{3} \right)} + 6 x y^{\frac{5}{2}} \cos{\left(y^{3} \right)}}