) Find the absolute extrema of the function f(x. y)1+y-x - y on the closed and bounded region D between the graphs of the horizontal line yí° and the unit parabola y = x. Give the locations of any extrema, absolute or relative, as ordered triples of the form (xyx.y)). 2) Find all critical points for the function f(x,y) = x2ye_z?ã. HINT: You will need to observe that af ax of and use the fact that e-r'ã#0. Don't be surprised if there are a lot of critical points. 3) Find and classify all critical points of the function f(x.y) x2+x +2xy. 4) Find the maximum value of the function f (x, y,z) - xyz on the plane x ty+ 8. 5) Evaluate the iterated integral dx dy o -21 +y2 6) Calculate the exact value of the double integral where R = [13] x [12].