
question
Posted:
Apr 5, 2014 1:49 AM


I am so sick of Mathematica. It no longer seems to be a package to do applied work, but more for the university types. I have spent several hours using several combinations of ?NumberQ in the following code, but still I get an error. Last weekend I spend several hours using FunctionExpand to get results I can read.
Any help appreciated.
r1=1; r2=2; beta2[t_]:={r1*Cos[2*Pi*t],r2*Sin[2*Pi*t]}
beta1[t_]:=beta2[t+4.8*t^2*(t1)^2]
q2[t_]:= FunctionExpand[beta2'[t]/Sqrt[Norm[beta2'[t]]],Assumptions>t\[Element] Reals && beta2'\[Element]Vectors[2,Reals]]
q1[s_]:=FunctionExpand[ beta1'[s]/Sqrt[Norm[beta1'[s]]],Assumptions>s\[Element] Reals&& beta2'\[Element]Vectors[2,Reals]]
a[t_, z_] := 2*q1[t].q2'[z] // FunctionExpand b[t_, z_] := q1[t].q2[z] // FunctionExpand c[t_, z_] := 2*q1'[t].q2[z] // FunctionExpand
F1[t_, z_] := c[t, z]/b[t, z] F2[t_, z_] := a[t, z]/b[t, z]
factor1[s_, z_] := Exp[NIntegrate[F2[s, u], {u, 0, z}]]
factor2[s_, z_] := Exp[NIntegrate[F2[s, u], {u, 0, z}]]
g[s_, z_?NumberQ] := NIntegrate[factor2[s, tau]*F1[s, tau], {tau, 0, z}]
y[s_, z_] := factor1[s, z]*g[s, z]
y[.2, .3]
I get the error
NIntegrate::nlim: _u_ = _tau_ is not a valid limit of integration

