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Topic: ComplexExpand off by a factor of (-1)?
Replies: 3   Last Post: Feb 23, 2013 7:01 AM

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Murray Eisenberg

Posts: 2,105
Registered: 12/6/04
Re: ComplexExpand off by a factor of (-1)?
Posted: Feb 23, 2013 7:01 AM
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Hint: in your expression, replace 2*I by 2*k and you'll see why Mathematica gave you the correct value, i.e., exactly what you asked for!
On Feb 22, 2013, at 1:05 AM, wrote:

> Would someone be able to help me understand why when I enter the expression:
> ComplexExpand[(E^(I*y) - E^(-I*y))/2*I] I get a result of -Sin[y] instead of Sin[y]?
> Thanks.
> Charles S.

Murray Eisenberg
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