$5\mathrm{.}37)$ Let $=(2+3)++().$ Evaluate $$ along the following paths $$:

a$)=22,=,=3$ from $=0$ to $=1$

b$)$ the straight lines from $(0,0,0)$ to $(0,0,1),$ then to $(0,1,1),$ and then to $(2,1,1)$

c$)$ the straight line joining $(0,0,0)$ and $(2,1,1)$