Re: problem with"Re" syntax

• To: mathgroup at smc.vnet.net
• Subject: [mg116829] Re: problem with"Re" syntax
• From: tarun dutta <tarunduttaz at gmail.com>
• Date: Wed, 2 Mar 2011 04:31:36 -0500 (EST)
• References: <ikan2k\$cdr\$1@smc.vnet.net> <ikihc8\$7nh\$1@smc.vnet.net>

```On Mar 1, 3:22 pm, "Sjoerd C. de Vries" <sjoerd.c.devr... at gmail.com>
wrote:
> The problem is not Re. It's that Mathematica assumes that your a, b, g
> and h functions may be complex valued. If that's not the case then you
> could use ComplexExpand to say so:
>
> ComplexExpand[Re[del]]
>
> g[0][t] g[1][t] + Sqrt[2] g[1][t] g[2][t] + Sqrt[3] g[2][t] g[3][t] +
>  2 g[3][t] g[4][t] + Sqrt[5] g[4][t] g[5][t] - h[0][t] h[1][t] -
>  Sqrt[2] h[1][t] h[2][t] - Sqrt[3] h[2][t] h[3][t] -
>  2 h[3][t] h[4][t] - Sqrt[5] h[4][t] h[5][t]
>
> Cheers -- Sjoerd
>
> On Feb 26, 12:10 pm, tarun dutta <tarundut... at gmail.com> wrote:
>
> > c[i_][t] = a[i][t] + I*b[i][t];
> > d[i_][t] = g[i][t] + I*h[i][t];
> > del = Together[Sum[Sqrt[i]*d[i - 1][t]*d[i][t], {i, 0, 5}]]
> > Re[del]
>
> > the problem is that after executing the program, as output I am not
> > able to get only the real part of the expression(del).the output
> > contains the whole expression though i am using "Re" term.
>
> > some valuable insight will be much appreciated.
> > regards,
> > tarun

thanks sjoerd.but I am using mathematica version-7 so using
ComplexExpand am not able to get the expected term and it is right
that a,b,g,h all are real quantity.
thanks again
regards,
tarun

```

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