Re: nested SetDelayed

*To*: mathgroup at smc.vnet.net*Subject*: [mg113408] Re: nested SetDelayed*From*: Vince Virgilio <blueschi at gmail.com>*Date*: Wed, 27 Oct 2010 05:17:11 -0400 (EDT)*References*: <ia3mr3$rl4$1@smc.vnet.net>

On Oct 25, 6:40 am, O <kakabo... at gmail.com> wrote: > hello, > maybe somebody can explain what i'm doing wrong in this SIMPLE > example: > > In[1] := f[v_, k_] := Sin[v*k] > In[2] := test[v_] := NIntegrate[f[v, k], {k, 0, Pi}] > In[3] := FindRoot[test[x] == 1, {x, 1}] > > I have NIntegrate errors: > > NIntegrate::inumr: The integrand Sin[k x] has evaluated to non- > numerical values for all sampling points in the region with boundaries > {{0,3.14159}}. >> > NIntegrate::inumr: The integrand k Cos[k x] has evaluated to non- > numerical values for all sampling points in the region with boundaries > {{0,3.14159}}. >> > NIntegrate::inumr: The integrand k Cos[k x] has evaluated to non- > numerical values for all sampling points in the region with boundaries > {{0,3.14159}}. >> > General::stop: Further output of NIntegrate::inumr will be suppressed > during this calculation. >> > > and CORRECT answer: > Out[3] = {x -> 1.37697} > > Why expression `test` is evaluated with nonnumerical arguments?? > > I guess my VisualBasic oriented brain can't understand how SetDelayed > work and how i should use it. > > Thanks Other posts have more direct answers. So, stepping back a bit, here is a page in the Doc Center that gives more context: tutorial/UnconstrainedOptimizationSymbolicEvaluation Vince