Question

if z = -1 + i be a complex number . then arg (z) is equal to
1) π
2) 3π / 4
3) π /4
4)0
plzzz answer my question quickly plzzz guys​

Answer 1

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Answer 2

Answer:

Let d be the common difference. The sum of the first 12 terms is then

4+(4+d)+(4+2d)+ ... +(4+11d)

Recall now the key fact that the sum of the first n integers is (n+1)n2. Obviously you can write the expression for the sum of the first 8 terms similarly and it should now reduce just to arithmetic..........