Explicit integration

[garry_mack]

Ive been asked to EXPLICITLY evaluate A line intergral G = <y, -x>

along a contour C where x(t) = 2t and y(t) = t. with 0 <= t <= 1.

I know that at normal integral for this problem may look something like INTG((x(t).y(t))ds) but I cant seem to find anything on explicit integration in my text books and even wikipedia.

thanks -
Garrymack