2. (3 pts) For each of the functions below, find the first and second partial derivative with respect to eachvariable, as well as the cross-partial derivative (5 derivatives total). The first case is done for you. \text { a. } f(x, y)=5 x^{2} y \text { b. } f\left(x_{1}, x_{2}\right)=x_{1}^{2}-x_{1} x_{2} \text { c. } f\left(x_{1}, x_{2}\right)=3 x_{1}^{\frac{1}{3}} x_{2}^{3} \text { d. } f\left(x_{1}, x_{2}\right)=x_{1}+\frac{x_{2}}{x_{1}} \text { e. } f(x, z)=\frac{5 x+10 z}{x^{3}} \text { f. } f(x, y)=\frac{x y+x^{2}}{x+y} \text { g. } f(x, y)=\sqrt{x^{2}+y}

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