Hi I'm studying for a calculus exam and I'm a little stuck on finding the extrema for multivariable functions. For the particular question I'm trying to do now I need to find and classify the extrema for the function f(x,y) = (4x^2)(e^y) - 2x^4 - e^4y. I can find the first derivatives, being fx = 8xe^y - 8x and fy = (4x^2)(e^y) - 4e^4y and I know I have to let them be equal to 0 to find where the extrema are located but I'm not sure how to do that. I guess it's just the exponentials that are throwing me off. Any help would be appreciated.