Skip to main content
ttokoro
21-Topaz I
21-Topaz I
October 2, 2021
Solved

Integral sinc(x)

  • October 2, 2021
  • 4 replies
  • 6134 views

Quora shows interesting math. Prime 7 can show third equation is also pi.

I want to calculate until

ttokoro_0-1633168449646.png

and 

ttokoro_1-1633168484513.png does not show pi/2

 

 

image.pngimage.pngimage.png need very long time to solve.

Best answer by ttokoro

Borwein integral - Wikipedia

Quora is true.

image.png

4 replies

21-Topaz II
October 2, 2021

Please note that the definition of Mathcad's sinc function differs from that used elsewhere. The Mathcad definition is sinc(x) = sin(x)/x, while on certain texts it is defined like this: sinc(x) = sin(Ï€x) / (Ï€x) so in the comparison of the calculated values and those of the text there may be differences. I'm referring to Mathcad 15. Certain errors in MC15 have been fixed in Prime 7.

answer to ttokoro.jpg

23-Emerald IV
October 3, 2021

Maple says:

LucMeekes_1-1633257613804.png

 

Luc

23-Emerald IV
October 3, 2021

LucMeekes_0-1633257003438.png

Luc

ttokoro
21-Topaz I
ttokoro21-Topaz IAuthor
21-Topaz I
October 5, 2021

image.png

This is limit of Prime 7.

 

ttokoro_0-1633432265030.png

Therefore, I can't get the results shown by Quora web site.

 

ttokoro_1-1633432425598.png

 

 

t.t.
21-Topaz II
October 6, 2021

answer to ttokoro 1.jpg

ttokoro
21-Topaz I
ttokoro21-Topaz IAuthor
21-Topaz I
October 6, 2021

image.pngimage.png TOL=10^-3

ttokoro_0-1633562726618.pngTOL=10^-7

 

image.pngimage.pngimage.png

Therefore, Quora and Luc show the answer is pi/2 for n=0 to 6. But n>6 are not calculate symbolically when using 15 digit accuracy. May be n>6 also show pi/2 symbolically when calculate more digit accuracy. Or Quora is true mathematically.

t.t.
21-Topaz II
October 7, 2021

I use the sinc function according to the definition of the text reported here below. Sin (x) / x is something else ...

The Fourier.jpg

24-Ruby III
October 12, 2021

When I try to solve it (Mathcad 15 F000, Windows 7 x64, 16 GB of RAM), I get an error - "Internal error [1321]":

 

Pic-1.png