       Re: Plot works in Mathematca 7 but not in Mathematica 8

• To: mathgroup at smc.vnet.net
• Subject: [mg115871] Re: Plot works in Mathematca 7 but not in Mathematica 8
• From: Bob Hanlon <hanlonr at cox.net>
• Date: Sun, 23 Jan 2011 05:37:26 -0500 (EST)

```Works if you pull the function out of the Plot.

\$Version

"8.0 for Mac OS X x86 (64-bit) (November 6, 2010)"

f[ki_?NumericQ, h_, kn_?NumericQ, kr_?NumericQ] :=
Abs[((kn^2 - (kr + ki I)^2)*(4 h (Log[4 h/a] -
NIntegrate[(1 - Exp[I (kr + ki I) y Cos[kn y]])/y, {y, 0, 2}]) +
I/((kr + ki I) + kn) (Exp[I 2 ((kr + ki I) + kn) h] - 1) +
I/((kr + ki I) - kn) (Exp[I 2 ((kr + ki I) - kn) h] -
1)) - (kn^2 + (kr + ki I)^2)*
NIntegrate[Exp[I (kr + ki I) y] Sin[kn y]/y, {y, 0, 2}])]

h = 1; kn = Pi/h; kr = 3.050;

Plot[f[ki, h, kn, kr], {ki, -0.23, -.10}]

Bob Hanlon

---- "1.156" <rob at piovere.com> wrote:

=============
I've found very little to complain about using Mathematica 8 but I just ran into a
Plot which only displays the two plot axes, no graph. Fortunately I
still have Mathematica 7 installed and found that Mathematica 7 Plots this same code nicely.
Can anyone give me clues on what may make this work correctly in Mathematica 8?
Code below, thanks.

***************
h = 1; a = 0.0001; kn = Pi/h; kr = 3.050;
Plot[Abs[((kn^2 - (kr + ki I)^2)*
(4 h (Log[4 h/a] -
NIntegrate[(1 - Exp[I (kr + ki I) y Cos[kn y]])/y, {y, 0, 2}]) +
I/((kr + ki I) + kn) (Exp[I 2 ((kr + ki I) + kn) h] - 1) +
I/((kr + ki I) - kn) (Exp[I 2 ((kr + ki I) - kn) h] - 1) ) -
(kn^2 + (kr + ki I)^2)*
NIntegrate[
Exp[I (kr + ki I) y] Sin[kn y]/y, {y, 0, 2}])], {ki, -0.23, -.10}]
--

```

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