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Re: Putting an If in my function

• To: mathgroup at smc.vnet.net
• Subject: [mg101058] Re: [mg101039] Putting an If in my function
• From: Leonid Shifrin <lshifr at gmail.com>
• Date: Tue, 23 Jun 2009 07:03:32 -0400 (EDT)
• References: <200906220821.EAA09081@smc.vnet.net>

Hi,

I would suggest that you use pattern - matching instead of If:

Clear[fn];

fn[a_,g_,f_,x_,d_,w_]/;w==g:=d+a*f*x;

fn[a_,g_,f_,x_,d_,w_]:=
d (1+(Exp[g]-Exp[w])/f)^(f x)+(a (-1+(1+(Exp[g]-Exp[w])/f)^(f x))
f)/(Exp[g]-Exp[w]);


Regards,
Leonid



On Mon, Jun 22, 2009 at 1:21 AM, Lobotomy <labbman at gmail.com> wrote:

> Hi, this is my function
>
> #5 (1 + ((E^#2 - 1) - (E^#6 -
>            1))/#3)^(#3*#4) + (#1*((1 + (((E^#2 - 1) - (E^#6 -
>                 1))/#3))^(#3*#4) -
>        1))/(((E^#2 - 1) - (E^#6 - 1))/#3) &[a, g, f, x, d, w]
>
>
> in the case when w==g the denominator equals zero.
>
> in this case i would like to rewrite the formula above to the much
> simpler
> d+a*n. How is this done? I've tried
>
> If[w == g, % = d + a*n], but this is not working. Another thing is
> where to put the "If"
>
>

• References:
  • Putting an If in my function
    • From: Lobotomy <labbman@gmail.com>