3, Calculate the multiple (double) integral )/ of the scalar function ((x.y) in 2 variables, x, y. D followa: over the region D of the 2 dimensional xy space (plane), where f and D are described as De triangle ABC, with A= (0, -1), B= (1, 0), C= (0,1) 4, Calculate the multiple (triple) integral " of the (scalar) function ((x,y,z) in 3 variables, X. Y E. over the region D of the 3 dimensional xyz space, where I and D are described as follows; D- tetrahedron ABCD, with A= (0, 0, -1), D=(1, 0, 0), 0=(0, 1, 0), D= (0,0.1) (that is, A, D are on the z axis (at - 1 and 1, resp) and B, C are on the x and y axes, resp, at 1, 1, reap (The Fubini set up as an iterated integral (of length 3) is sufficient) had a t towill