Search All of the Math Forum:

Views expressed in these public forums are not endorsed by NCTM or The Math Forum.

Notice: We are no longer accepting new posts, but the forums will continue to be readable.

Topic: how solve this equation with one unknown?
Replies: 6   Last Post: May 6, 2013 10:38 AM

 Messages: [ Previous | Next ]
 Nasser Abbasi Posts: 6,677 Registered: 2/7/05
Re: how solve this equation with one unknown?
Posted: May 6, 2013 9:14 AM

On 5/6/2013 7:59 AM, ghasem wrote:
>
> =======================================
> ok,you right.
> my code (with correction) is as following:
> my code is :
> gr1 = sqrt(-100 - my_var^2);

EDU>> gr1 = sqrt(-100 - my_var^2);
Undefined function or variable 'my_var'.

<SNIP>

>
> I want to solve "det_A" to obtain "my_var" value.
>but I don't know how introduce "my_var" in gr1,gr2 and gr3,such that in "det_A",
>exist "my_var" as a variable.
> if I use from " syms my_var",therefore I can not use from fsolve.
> obviously,in the above,I get this error:
> ??? Undefined function or variable 'my_var'.
> how introduce "my_var" to matlab?
> ghasem
>

-----------------------
syms my_var;
EDU>> det_A

det_A =
- 15000*(- my_var^2 - 70)^(1/2)*(- my_var^2 - 150)^(1/2)*
besselk(1, (- my_var^2 - 70)^(1/2))*
besseli(0, (- my_var^2 - 100)^(1/2))*besseli(0, (- my_var^2 -
....
<snip>

solve(det_A)
------------------------

ans =
9.4713545425002677821820583754265*i

--Nasser

Date Subject Author
5/6/13 Nasser Abbasi
5/6/13 ghasem
5/6/13 ghasem
5/6/13 Nasser Abbasi
5/6/13 ghasem