Basic Examples 
(2)
 

Test whether an expression represents a quadratic function of a given variable:
In[1]:=
[◼]
QuadraticFunctionQ
[ax^2+bx+c,x]
Out[1]=
True
In[2]:=
[◼]
QuadraticFunctionQ
[4x-Pi0,x]
Out[2]=
False
———
Test whether a given expression represents a quadratic function of a list of variables:
In[3]:=
[◼]
QuadraticFunctionQ
[(x^2+1)Log[y],{x}]
Out[3]=
True
In[4]:=
[◼]
QuadraticFunctionQ
[(x^2+1)Log[y],{x,y}]
Out[4]=
False
In[5]:=
[◼]
QuadraticFunctionQ
[ax^2+bx+cxy+dy^2,{x,y}]
Out[5]=
True

Properties and Relations 
(3)
 
