quadratic equation pattern matching

[Former user]

How can I check if an IExpr is a quadratic equation with the pattern matching?

[Axel Kramer]

If you're logged in the online interface with your google account,

symjaweb.appspot.com

you can define these rules:

$QuadraticQ(u_,x_Symbol) := 
  $PolyQ(u,x,2);
$PolyQ(u_,x_Symbol,n_Integer) :=
  If(ListQ(u), Catch(Scan(Function(If(Not($PolyQ(#,x,n)),Throw(False))),u); True),
  PolynomialQ(u,x) && Exponent(u,x)==n && Coefficient(u,x,n)=!=0)

>>> $QuadraticQ(4*x^2+3*x,x)
True

>>> $QuadraticQ(3*x,x)
False

If you would like to use the library in single user mode in a Java program, you can define:

Config.SERVER_MODE = true;

at the start of the program and can use QuadraticQ and PolyQ directly as identifiers without the leading '$' character.