Search All of the Math Forum:
Views expressed in these public forums are not endorsed by
NCTM or The Math Forum.



Numerical solution from Module
Posted:
May 9, 2014 2:07 AM


Hello every one,
Here is a simple question. Say I define a function
In[14]:= f[x_] := a*x^2 + b*x + c
Then I use Module to frame the solution of f[x] ==0
In[15]:= soln[a_, b_, c_] := Module[{}, xsoln = Solve[f[x] == 0 , x]; x /. xsoln]
When I enter numerical values for parameters a, b, and c in the module, f[x] never sees these numerical values, and returns a symbolic solution.
In[11]:= soln[1, 3, 2]
Out[11]= {(b  Sqrt[b^2  4 a c])/(2 a), (b + Sqrt[b^2  4 a c])/(2 a)}
But I want the module to return a numerical solution as:
{{x > 1}, {x > 2}}
My question is: without bringing f[x] explicitly into the Module function, and without redefining f as f[a_,b_,c_][x] := a*x^2+b*x+c, how can I get the module to return a numerical solution?
Thanks  Rob Chai



