2(c) take any (x,y) - suppose (0,3) (-1,-4) (-2,4) (3,-2)
then f(x,y) = (0-3,0+3) = (-3,3)
= (-1+4, -1-4) = (-3,-5)
= (-2-4, -2+4) = (-6,2)
= (3+2, 3-2) = (5,1)
so the range could be in any quadrant - matlab pura plane gets covered anyway.
(others please correct me if the reasoning is wrong!)
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