Use implicit differentiation where LaTeX:  \displaystyle y is a function of LaTeX:  \displaystyle x to find the derivative of LaTeX:  \displaystyle - \sqrt{x} \log{\left(y \right)} + e^{x}=49

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