If 
be the 
roots of unity, then the value of 
is equal to
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
Question ID - 103231 | SaraNextGen Top Answer
If be the roots of unity, then the value of is equal to
a)
b)
c)
d)
None of these
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If |
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a) |
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b) |
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c) |
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d) |
None of these |
1 Answer
127 votes
Answer Key / Explanation : (c) -
(c)
Since, 
are 
roots of unity.
Therefore,
Differentiating both sides w.r.t. 
we get
Putting 
on both sides, we get
Now,
127 votes
Answer Link
127