If be the roots of unity, then the value of is equal to |
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a) |
b) |
c) |
d) |
None of these |
If be the roots of unity, then the value of is equal to |
|||||||
a) |
b) |
c) |
d) |
None of these |
(c)
Since, are roots of unity.
Therefore,
Differentiating both sides w.r.t. we get
Putting on both sides, we get
Now,