Question

If u=f(r) where r^(2)=x^(2)+y^(2) show that (d^(2)u)/(dx^(2))+(d^(2))/(dy^(2)) =f''(r)+(1)/(r)f'(r)​

Answer 1

Answer:

Answer:If u=f(r) where r^(2)=x^(2)+y^(2) show that (d^(2)u)/(dx^(2))+(d^(2))/(dy^(2)) =f''(r)+(1)/(r)f'(r)