Use implicit differentiation where LaTeX:  \displaystyle y is a function of LaTeX:  \displaystyle x to find the derivative of LaTeX:  \displaystyle 5 x^{2} \log{\left(y \right)} - 8 y^{2} \cos{\left(x^{3} \right)}=-23

Taking the derivative of both sides using implicit differentiation gives: LaTeX:   24 x^{2} y^{2} \sin{\left(x^{3} \right)} + \frac{5 x^{2} y'}{y} + 10 x \log{\left(y \right)} - 16 y y' \cos{\left(x^{3} \right)} = 0  Solving for LaTeX:  \displaystyle y' gives LaTeX:  \displaystyle y' = - \frac{2 x y \left(12 x y^{2} \sin{\left(x^{3} \right)} + 5 \log{\left(y \right)}\right)}{5 x^{2} - 16 y^{2} \cos{\left(x^{3} \right)}}