SamverkanFlervariabelanalysLIU

a) \displaystyle f'_{x_{1}}=\frac{x_{1}}{|\mathbf{x}|}, \displaystyle f'_{x_{2}}=\frac{x_{2}}{|\mathbf{x}|}, \displaystyle f'_{x_{3}}=\frac{x_{3}}{|\mathbf{x}|}

b) \displaystyle f'_{x_{1}}=2x_{1}, \displaystyle f'_{x_{2}}=2x_{2}, \displaystyle f'_{x_{3}}=2x_{3}

c) \displaystyle f'_{x_{1}}=\frac{1}{1+|\mathbf{x}|}\; \frac{x_{1}}{|\mathbf{x}|}, \displaystyle f'_{x_{2}}=\frac{1}{1+|\mathbf{x}|}\; \frac{x_{2}}{|\mathbf{x}|}, \displaystyle f'_{x_{3}}=\frac{1}{1+|\mathbf{x}|}\; \frac{x_{3}}{|\mathbf{x}|}