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Question on line integrals.. Really stuck!

Hi, Ive been trying to figure this out for a while and not getting anywhere, don't really understand them.

The question is,

L is a straight line in the xy plane from (0,0) to (1,1). Write down the parametric function for L. Evaluate Integral(F)dr for F(r)=(y,0)

So is the parametric equations y=t and x=t ??

I have no idea what I'm doing. :confused: :frown:
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Original post by Ouzo
Hi, Ive been trying to figure this out for a while and not getting anywhere, don't really understand them.

The question is,

L is a straight line in the xy plane from (0,0) to (1,1). Write down the parametric function for L. Evaluate Integral(F)dr for F(r)=(y,0)

So is the parametric equations y=t and x=t ??

I have no idea what I'm doing. :confused: :frown:

Your parametrisation is correct, although make sure you specify what the range of t is.

Go through your notes (I'm assuming you have some) and you should find that for a field F=<P,Q>\mathbf{F} = <P,Q>, the line integral along a path C can be written as:
CFdr=CPdx+Qdy\displaystyle \int_C \mathbf{F}\cdot d\mathbf{r} = \int_C Pdx + Qdy

where F=<P,Q> & r=<x,y>\mathbf{F} = <P,Q>\ \&\ \mathbf{r} = <x,y> and <> denotes a vector. The expression on the RHS just comes from computing Fdr\mathbf{F}\cdot d\mathbf{r}.

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