Math Is Fun Forum

coolwind

Member

Registered: 2005-10-30

Posts: 30

A integral problem~~

∫(sinc^2)4f df   ,where integral   range -∞ to +∞

Thanks~~!!

mathsyperson

Moderator

Registered: 2005-06-22

Posts: 4,900

Re: A integral problem~~

If you're integrating with respect to f, then isn't sin²c just a constant?

If so, you can move it outside the integral and have sin²c∫4f df.

4f integrates quite easily, into 2f² +c.

But then if you're integrating between +∞ and -∞, then your answer would be 0.

So I could well have misinterpreted something.

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Why did the vector cross the road?
It wanted to be normal.

polylog

Member

Registered: 2006-09-28

Posts: 162

Re: A integral problem~~

He means the sinc function sinc(x).

http://mathworld.wolfram.com/SincFunction.html