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 |

1 Answer

127 votes

**(c)**

Since, are roots of unity.

Therefore,

Differentiating both sides w.r.t. we get

Putting on both sides, we get

Now,

127 votes

127