# Thread: Global min and max multivariable

1. ## Global min and max multivariable

Can someone help me get the Global min and max. I know how to find the critical points but I'm not sure how to tell if its the global max and min. Here is the problem:

F(x,y)=4e^-(4x^2+8y^2), 4x^2+8y^2 < or = to 3 ( just in case the above picture doesnt paste right once thread is posted)

Thanks

2. The max and min may occur at a critical point inside the set, or on the boundary of a set. Here, that is particularly easy because on the boundary, $4x^2+ 8y^2= 3$ so your function is just $f(x, y)= 4e^{-3}$, a constant.

Evaluate the function at all critical points inside the set and on the boundary and see which are smallest and largest!