Find the line integrals of $\mathbf{F}$ from (0,0,0) to (1,1,1) over each of the following paths in the accompanying figure.
a. The straight-line path $C_{1}: \mathbf{r}(t)=t \mathbf{i}+t \mathbf{j}+t \mathbf{k}, \quad 0 \leq t \leq 1$
b. The curved path $C_{2}: r(r)=r i+t^{2} j+r^{4} k, \quad 0 \leq t \leq 1$
c. The path $C_{3} \cup C_{4}$ consisting of the line segment from (0,0,0)
to (1,1,0) followed by the segment from (1,1,0) to (1,1,1)
(FIGURE CAN'T COPY)
$$\mathbf{F}=3 y \mathbf{i}+2 x \mathbf{j}+4 z \mathbf{k}$$