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February 28th, 2008, 02:00 PM   #1
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Sine/Cosine Integral values

I don't know how to use cosine integrals or sine integrals - but I had this problem:

[-((p*i)/2))Ci(p/2)] + [(p/2)Si(p/2)] + [((p*i)/2)Ci(-p/2)] + (p/2)Si(-p/2)]= ?

Where p=pi, i=the imaginary unit, Ci=Cosine integral, Si=Sine integral

Can anyone provide an answer to the above value?
karel747 is offline  
 
February 28th, 2008, 06:11 PM   #2
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Greetings:

The equation simplifies to zero. Note that cos(pi/2) = cos(-pi/2) = 0.

Thus we are left with (p/2)Si(p/2) + (p/2)Si(-p/2) = pi/2 - pi/2 = 0.

Regards,

Rich B.
rmath4u2@aol.com
nikkor180 is offline  
February 28th, 2008, 08:32 PM   #3
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No, I don't mean cos(pi/2) or cos(-pi/2) - I know what that is. What I'm trying to do is a cosineintegral/sineintegral. But I don't know how to use them or evaluate them.
Can anyone elaborate on how to find the cosineintegral of (pi/2) and (-pi/2)
and the sineintegral of (pi/2) and (-pi/2)?
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February 29th, 2008, 09:16 AM   #4
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Well, it's true that Si(-x)=-Si(x). This cancels the sinintegral. The Ci(-x) for x>0 is, however, not defined. Still, Mathematica gives the value of -pi^2/2.
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