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15. Evaluate the following limits. (a lim |z - 21 1+1 2x - 4 (b) lim a - 21 x-+2+ 2x - 4 (c) lim |2 - 21 x-+2- 2x - 4 (d) lim |2 - 2 x-+0 2x - 4 (e) lim |z - 2 2+-00 2x - 4 16. A rectangular box with square base and no top is to be constructed out of 4m of material. Fins the maximum volume of the box