Use implicit differentiation where LaTeX:  \displaystyle y is a function of LaTeX:  \displaystyle x to find the derivative of LaTeX:  \displaystyle - 6 \sqrt{2} \sqrt{x} e^{y^{2}} + 5 \log{\left(x \right)} \cos{\left(y \right)}=-23

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