# Chapter 15 - Differentiation in Several Variables - 15.3 Partial Derivatives - Exercises - Page 781: 27

$$W_r= e^{r+s}, \quad W_s= e^{r+s} .$$

#### Work Step by Step

Recall that $(e^x)'=e^x$ Since $W=e^{r+s}$, then by using the chain rule, we have $$W_r= e^{r+s} (1)=e^{r+s}, \quad W_s= e^{r+s}(1)=e^{r+s} .$$

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