
A vector equation thingy
Calculate $\displaystyle \int_{C}f(X).dX$ where $\displaystyle f(x,y)=(x^2+xy,yx^2y)$ and C is parametrized by $\displaystyle x=t, y= \frac{1}{t} \; (1\leq t \leq 3)$
I'm not really sure how to go about this. This is what I've attempted:
$\displaystyle x=t \Rightarrow \tfrac{\delta x}{\delta t} = 1$
$\displaystyle y= \tfrac{1}{t} \Rightarrow \tfrac{\delta y}{\delta t} = \tfrac{1}{t^2}$
$\displaystyle \int_{C}f(X).dX = \int_{C} (x^2+xy).\partial x + (yx^2y).\partial y = \int_{1}^{3} (t^2+1\frac{1}{t^3}+\frac{1}{t}).\partial t $
integrating that makes for a unpleasant mess: $\displaystyle \frac{t^3}{3}+t+\frac{1}{2t^2}+ln(t)$ which is why I'm wondering if I'm doing this right.

Believe it or not, that is exactly right!(Clapping)

Also try
$\displaystyle \int_{C}f(X(t))\cdot X'(t) dt$