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1. [1 pt] Express cos 60 as a polynomial of cos 0: cos 60 = 2. [1 pt] Let w = (1 + i) Then Arg(w4)= V2 3. [1 pt] Suppose that z = 3 - i is a root of the equation ar +br + cr +d=0, a,b,c,deR then (a) It has another root z = 3 + i. (b) it might have no roots in R. (c) it has in total 7 roots in C, some of them might be identical. (d) it has in total 7 roots in C, none of them could be identical