error while using ezplot

Hi, all.

 d = x^2 –6*x – 12;

 >> ezplot(d)
 Error using inlineeval (line 15)
 Error in inline expression ==> x.^2 –6.*x – 12
 Error: The input character is not valid in MATLAB statements or
 expressions.

 Error in inline/feval (line 34)
        INLINE_OUT_ = inlineeval(INLINE_INPUTS_, INLINE_OBJ_.inputExpr,
        INLINE_OBJ_.expr);

 Error in ezplotfeval (line 52)
    z = feval(f,x(1));

 Error in ezplot>ezplot1 (line 469)
    [y, f, loopflag] = ezplotfeval(f, x);

 Error in ezplot (line 145)
    [hp, cax] = ezplot1(cax, f{1}, vars, labels, args{:});

what is the problem here?

Answer 1

[Geoff Hayes]

The first input to ezplot must e a function handle or a string (see http://www.mathworks.com/help/matlab/ref/ezplot.html for details). Your variable d is neither - are you using the Symbolic Math Toolbox with a previous command like sym x in order to get that command to evaluate successfully?

I was able to plot this function as follows

d = 'x.^2 - 6*x - 12'
ezplot(d)

or as

func = @(x)x.^2 - 6*x - 12
ezplot(func)

Note the addition of the period at x.^2 so that func can evaluate an input vector rather than just single elements.

Answer 2

[math search]

I have never used those toolboxes. Just trying to learn some basic info and thank you for the interest.

Answer 3

[gh y]

Some versions of MATLAB can plot a function using ezplot(2014b) while another version(newer versions) cant plot the same code and encounters error. however I didnt test using dot before ^ but found out that same code coudnt be run in two different versions.

Answer 4

[Walter Roberson]

The problem is that the inline function was defined using en-dash, char(8211), U+2013, instead of regular hyphen or minus, char(45), U+002d