1. The problem statement, all variables and given/known data Find the area enclosed by the hyperbola: 25x^2-4y^2=100 and the line x=3 using the green's theorem 2. Relevant equations Green's theorem: [tex]\int_C[Pdx+Qdy]=\int\int(\frac{\partial Q}{\partial x}-\frac{\partial P}{\partial y})dxdy[/tex] 3. The attempt at a solution We can write the area of the domain as: area=[tex]\frac{1}{2}\int(xdy-ydx)[/tex] I know what the graph looks like and i know the parametrisation: x=2cosht y=bsinht but i am to use: area=[tex]\frac{1}{2}\int(xdy-ydx)[/tex] what would be the limits of integration?
The t limits for the hyperbolic segment of the parametrization are where x=3, i.e. 3=2*cosh(t), yes? Don't forget you need a separate parametrization for the linear part of the boundary x=3 and don't forget to choose a consistent orientation for the two line integrals.
thanks for the limits, i agree. When i parametrize the linear part at the boundary x=3, how does this effect the integrand?
The integrand is completely different. To do the line part you need to write an x(t) and y(t) that parametrize the line x=3.
Oh right i see. so when i do that, when i find x(t) and y(t) for the line, and the X(t) and Y(t) for the hyperbola part, how do i out this in the integrand? I mean for the xdy part, is this: (x(t)+X(t))dy(t) ?
Why don't you just do two separate line integrals instead of trying to mix them up? That's what I would do.