We have four rules of differentiation.
Sum Rule: \( \frac{\mathrm{d}}{\mathrm{d}x} [\mathrm{f}(x)+\mathrm{g}(x)] = \frac{\mathrm{d}}{\mathrm{d}x} \mathrm{f}(x) + \frac{\mathrm{d}}{\mathrm{d}x} \mathrm{g}(x) \)
Product Rule: \( \frac{\mathrm{d}}{\mathrm{d}x} [\mathrm{f}(x) \cdot \mathrm{g}(x)] = \frac{\mathrm{d}}{\mathrm{d}x} \mathrm{f}(x) \cdot \mathrm{g}(x) + \mathrm{f}(x) \cdot \frac{\mathrm{d}}{\mathrm{d}x} \mathrm{g}(x) \)