Quick question:

How do I plot the following in MATLAB:

$\displaystyle 3x^2 - 4xy + 3y^2 = 20$

cheers

edit:

nevermind, think I've go it now:

>> syms x y; quad = '3*x^2-4*x*y+3*y^2-20'; ezplot(quad,[-4,4,-4,4])

appears to work.

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- May 31st 2008, 07:40 PMDr ZoidburgMATLAB - plotting a quadratic
Quick question:

How do I plot the following in MATLAB:

$\displaystyle 3x^2 - 4xy + 3y^2 = 20$

cheers

edit:

nevermind, think I've go it now:

>> syms x y; quad = '3*x^2-4*x*y+3*y^2-20'; ezplot(quad,[-4,4,-4,4])

appears to work. - Jun 15th 2008, 04:14 AMCaptainBlack
When asking questions about Matlab please make it clear if you want to use the symbolic processor (some of us think of this as an extra - since we don't get it unless we pay many £100's extra).

(The symbolics are done by Maple not by Matlab so its always odd to see such questions presented as Matlab questions)

RonL - Jun 15th 2008, 05:25 PMDr Zoidburg
sorry, I didn't know that symbolics wasn't a standard part of MATLAB. I know eff-all about using MATLAB (this year is my first time ever). I found the above solution on-line and tried it out. It worked, which I guess means the MATLAB I'm using has MAPLE installed.

Out of interest, how would I plot the above equation without using sym?