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**Apprentice123** Calculate the circulation of vector field F arrond $\displaystyle \alpha$

1) $\displaystyle F(x,y) = (x-y)i + (x+y)j$ and $\displaystyle \alpha$ is the closed polygonal ABCDA traveled once in anticlockwise joining the points $\displaystyle A(1,0)$, $\displaystyle B(1,2)$, $\displaystyle C(0,2)$ and $\displaystyle D(0,1)$.

My solution:

Using green i have 2

The circulation is $\displaystyle \frac{1}{2}(A1+A2) = \frac{3}{4}$

A1 = $\displaystyle 1*1=1$

A2 = $\displaystyle \frac{1*1}{2}$

Is correct ?

2) $\displaystyle F(x,y) = (x+2xy)i + (y+x^2)j$ and $\displaystyle \alpha : |x| + |y| = 1$