Evaluate the line integral $$\int_C (x+2y)dx + x^2dy,$$ where $C$ consists of line segments from $(0,0)$ to $(2,1)$ and from $(2,1)$ to $(3,0)$.
How do you solve this? I split them up but got a negative answer.
For $C_1$ got, $\langle t, 1/2t\rangle$, $0 \leq t \leq 2$.
For $C_2$ got, $\langle t, t-3\rangle$, $2 \leq t \leq 3$.