MR. W.H.L. RUSSELL ON THE THEORY OF DEFINITE INTEGRALS.
159
and we find from this the series
Whence we find, putting for ,
Next consider the symbolical equation
, where ;
and assume as the transformed equation
.
Then
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and
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where , , are the three cube roots of unity.
Hence
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We must determine , , according to the series we have to sum.
If
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we find
Whence
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