Answer
See the explanation.
Work Step by Step
Consider a vector function $r(t)$, which is equal to $\lt a(t), b(t), c(t) \gt;x \leq t \leq y$. Then, the length of the space curve is defined as:
$ L=\int_x^y|r'(t)|dt=\int_x^y\sqrt {[a'(t)]^2+[b'(t)]^2+[c'(t)]^2}dt$
