Line Integral - Vector Calculus

cristina89
Messages
29
Reaction score
0

Homework Statement


Calculate the line integral:
f(x,y) = (x² - 2xy)î + (y² - 2xy)j, between the points (-1,1) and (1,1) along the parabola y = x².
(resp: -14/15)


The attempt at a solution
I thought something like this: substitue y = x², and then integrate de f(x,y). And then evaluate from -1 to 1, but it didn't work, obviously. How should I start solving this? I think I didn't get the concept about this kind of exercise...
 
Physics news on Phys.org
If it didn't work then you must have made an error in the integrall. What, exactly, did you do?

The integral of this will be \int (x^2 - 2xy)dx+ (y^2- 2xy)dy[//itex]. Did you remember to put dy in terms of x also?
 
HallsofIvy said:
If it didn't work then you must have made an error in the integrall. What, exactly, did you do?

The integral of this will be \int (x^2 - 2xy)dx+ (y^2- 2xy)dy[//itex]. Did you remember to put dy in terms of x also?
<br /> <br /> Ahh, that&#039;s exactly what I was forgetting! Thank you!
 
There are two things I don't understand about this problem. First, when finding the nth root of a number, there should in theory be n solutions. However, the formula produces n+1 roots. Here is how. The first root is simply ##\left(r\right)^{\left(\frac{1}{n}\right)}##. Then you multiply this first root by n additional expressions given by the formula, as you go through k=0,1,...n-1. So you end up with n+1 roots, which cannot be correct. Let me illustrate what I mean. For this...
Back
Top