Re: NIntegrate of Oscillatory integrand
- To: mathgroup at smc.vnet.net
- Subject: [mg94291] Re: NIntegrate of Oscillatory integrand
- From: dh <dh at metrohm.com>
- Date: Wed, 10 Dec 2008 04:43:14 -0500 (EST)
- References: <ghlml2$km8$1@smc.vnet.net>
Hi, you should write a more precise question. What is the integration variable, fist I assumed t but as you mentioned f[k] to be decreasing, it is probably k. 1/p is just a constant. t is a constant too. k f[k] t approaches a constant in the limit. Therefore Cos[ A - k f(k) t] approaches a constant too. The first term is simply oscillating with mean zero. If the limit of Cos[ A - k f(k) t] is differnt from zero, your integral diverges. If the limit of Cos[ A - k f(k) t] is zero, the integral does not exist. hope this helps, Daniel ventutech at gmail.com wrote: > Do someone has an idea how can I do the numerical integral > > Int_0_to_inf (1/p)( Cos[ A - k t] - Cos[ A - k f(k) t]) where f(k) is > an arbitrary decreasing function (besselK0, or just a gaussian..) > > Oscillatory and DoubleExponential methods don't work... > > D. >