1. [SOLVED] Line Integral.

Hello
find the line integral $\displaystyle \int_C ydx+zdy+xdz$
where C consist of line segement C1 from A(2,0,0) to B(3,4,5) followed by C2 from B(3,4,5) to C(3,4,0)
It is not hard I know.
Lets focus on C1:
By finding the parametric equations for this line, we will get:
$\displaystyle x=2+t$
$\displaystyle y=4t$
$\displaystyle z=5t$
Now, finding dx, dz .. etc and substitute them in the integral, easy.
But the problem how did we know that t is from 0 to 1 ???!

2. Never Mind, I got it
I got it
I said that : "Am Professor"