Evaluating quadratic functions

[hanrahat]

I'm having trouble understanding how to evaluate and plot quadratic functions.
Here's a sequence that explains what I'm trying to accomplish.  In particular,
I don't understand the error message "error: for A^b, A must be square" It 
doesn't
seem that A being square has anything to do with the function.

Can anyone help me understand how to do this?

Thanks,

-- Tom

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octave:1> x = 1:1:2;
octave:2> sqrt(x)
ans =
 
  1.0000  1.4142
 
octave:3> exp(x)
ans =
 
  2.7183  7.3891
 
octave:4> function retval = linear(x)
> retval = x + 1;
> endfunction
octave:5> linear(x)
ans =
 
  2  3
 
octave:6> function retval = quad(x)
> retval = x^2;
> endfunction
octave:7> quad(x)
error: for A^b, A must be square
error: evaluating binary operator `^' near line 2, column 11
error: evaluating assignment expression near line 2, column 8
error: called from `quad'
octave:7>



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