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From: Mohammad on 14 Jul 2010 13:13
Hi guys,

So usually when I use fzero, I have one variable that I'm trying to solve for. Currently, I still have one variable I want to solve for, but I have other variables I would input myself:

f = input('Please enter focal length. [f]: ');
h = input('Please enter lens diameter. [h]: ');
n = input('Please enter refractive index. [n]: ');
z = @(x)(n-1)^2*x/(n(((h/2)^2+(x/2)^2)/x)^2)-1/f;
d = fzero(z,2);

I'm trying to store a value for d (lens width) but when I run the program I get:

FZERO cannot continue because user supplied function_handle ==>
@(x)(n-1)^2*x/(n(((h/2)^2+(x/2)^2)/x)^2)-1/f
failed with the error below.

Attempted to access n(8.5); index must be a positive integer or logical.

Error in ==> Narutocool at 6
d = fzero(z,2);

A small fix for this would be highly appreciated

Cordially, Mohammad
From: Steven Lord on 14 Jul 2010 13:18

"Mohammad " <jaber2(a)uni.uiuc.edu> wrote in message
news:i1kr73$b00$1(a)fred.mathworks.com...
> Hi guys,
>
> So usually when I use fzero, I have one variable that I'm trying to solve
> for. Currently, I still have one variable I want to solve for, but I have
> other variables I would input myself:
>
> f = input('Please enter focal length. [f]: ');
> h = input('Please enter lens diameter. [h]: ');
> n = input('Please enter refractive index. [n]: ');
> z = @(x)(n-1)^2*x/(n(((h/2)^2+(x/2)^2)/x)^2)-1/f;

Did you forget a multiplication sign * immediately before the ((( in this
expression?

--
Steve Lord
slord(a)mathworks.com
comp.soft-sys.matlab (CSSM) FAQ: http://matlabwiki.mathworks.com/MATLAB_FAQ
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From: Mohammad on 14 Jul 2010 13:32
that fixed it oops... :) Thanks
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