Originally Posted by

**pakman** F, i, j, r, q, p are vectors

F(x,y) = (2xy)i - (x^2)j

div F(x,y) = 2y

curl F(x,y) = -4x which is not equal to zero, allowing no potential.

Now this is the confusing part. Work = 25/3

Here is how they got it

Row (or atleast I think that's what it is) is parameterized by r(t) = p + t(q-p)

x(t) = 1+t

y(t) = 3+t

p=<1,3>

q=<2,4>

0 <= t <= 1

INT(F dot dr) = INT(0 to 1) 2(1+t)(3+t)dt - (1+t)^2 dt

u = 1+t

du = dt

then on from there to get 25/3

My question is... what is all of that stuff for Work? I don't understand where the r(t) = p + t(q-p) comes from... same goes for all the values of x(t), y(t) etc...

Someone help please! I had to postpone my finals due to military training and now I've forgotten so much.