RE: using findroot for multiple functions

• To: mathgroup at smc.vnet.net
• Subject: [mg30361] RE: [mg30337] using findroot for multiple functions
• From: "David Park" <djmp at earthlink.net>
• Date: Sun, 12 Aug 2001 02:29:50 -0400 (EDT)
• Sender: owner-wri-mathgroup at wolfram.com

```Amy,

A good place to use a pure function. We Map the FindRoot function onto an
arbitrary list of values.

t /. FindRoot[(t - #)*Sin[t + #] + Sin[t - #]*Cos[t + #], {t, 0}] & /@ {1,
3,
7.5, 8, 8.1, 9}
{1., 0.0700271, -4.29968, 1.37411, 1.24612, 0.344576}

David Park

> From: Amy Sommer [mailto:amsommer at pacific.mps.ohio-state.edu]
To: mathgroup at smc.vnet.net
>
> I need to solve multiple equations varying one parameter.  I am able to do
> this if I vary the parameter in equal steps, but I have a list of numbers
> that I need to plug in.  Here is an example because my description
> probably is not very clear:
>
> Here is an example of what works:
>
> Table[t /.FindRoot[(t-a)*Sin[t+a] + Sin[t-a]*Cos[t+a], {t,0}],[a,1,10,.5]
>
> My problem comes in because I want have a list of values that are not in
> equal steps.  I have tried the following with no success:
>
> list = {1, 3.4, 99.1,100,109}
> ReplaceAll[[FindRoot[(t-a)*Sin[t+a] + Sin[t-a]*Cos[t+a],{t,0}],a-> list]
>
> If anyone has an idea on how I can get this to work, please let me know.
>
> Thanks,
> Amy Sommer
>
>

```

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