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Re: usage of TrigToExp?

• To: mathgroup at smc.vnet.net
• Subject: [mg95441] Re: [mg95431] usage of TrigToExp?
• From: DrMajorBob <btreat1 at austin.rr.com>
• Date: Mon, 19 Jan 2009 02:54:23 -0500 (EST)
• References: <200901181032.FAA13971@smc.vnet.net>
• Reply-to: drmajorbob at longhorns.com

I suspect you've given x a value, but I'm not sure what value would give  
those results.

TrigToExp[Cos[2 x]]

1/2 E^(-2 I x) + 1/2 E^(2 I x)

TrigToExp[Cos[y] Sin[x]]

1/4 I (E^(-I x) - E^(I x)) (E^(-I y) + E^(I y))

Bobby

On Sun, 18 Jan 2009 04:32:48 -0600, zatuch <zatuch at gmail.com> wrote:

> Hello,
> Results from function TrigToExp seemed weird to me. Could anyone
> please give me a good explanation on its usage. Thanks a lot.
>
> In[41]:= TrigToExp[Cos[2 x]]
> During evaluation of In[41]:= Nonreal::warning: Nonreal number
> encountered.
> Out[41]= Nonreal
>
> In[43]:= TrigToExp[Cos[y] Sin[x]]
> Out[43]= 0
>
> Zatuch
>



-- 
DrMajorBob at longhorns.com