Re: Simple indefinite integral disagrees with table

*To*: mathgroup at smc.vnet.net*Subject*: [mg28660] Re: Simple indefinite integral disagrees with table*From*: Ignacio Rodriguez <ignacio at sgirmn.pluri.ucm.es>*Date*: Sat, 5 May 2001 04:00:44 -0400 (EDT)*Organization*: UCM*References*: <9ctb6k$m4h@smc.vnet.net>*Sender*: owner-wri-mathgroup at wolfram.com

If you use brakets, Mathematica takes Cos to be a constant and just multiplies: Integrate[x Cos (a x),x] -> 1/3 a Cos x^3 This is just Integrate[a x^2 Cos,x]-> 1/3 a Cos x^3 If you want Cos to be the cosine function, just use Integrate[x Cos[a x],x] -> (Cos[a x]+a x Sin[a x])/a^2 which is what you have in your table. Mitch Berkson wrote: > The Mathematica solution to the indefinite integral below doesn't agree with > that found in my CRC tables. > > Integrate[xx Cos (aa xx), xx] > = (1/3) aa Cos xx^3 > > The CRC table gives: (1/aa^2) Cos (aa xx) + (xx/aa) Sin (aa xx) > > The Mathematica solution doesn't look right. Thanks for any help. > > Mitch Berkson -- Ignacio Rodriguez Ramirez de Arellano Unidad de RMN Universidad Complutense Paseo Juan XXIII, 1 Madrid 28040, Spain Tel. 34-91-394-3288 Fax 34-91-394-3245 e-mail: ignacio at sgirmn.pluri.ucm.es