Is f(x)=x^2-1 a quadratic function?

2 Answers
Aug 8, 2015

#f(x) = x^2-1# is a quadratic function

Explanation:

Any expression that can be written in the form:
#color(white)("XXXX")##f(x) = ax^2+bx+c#
is a quadratic function.

#f(x)=x^2-1#
is equivalent to #f(x) = 1 * x^2 +0 * x + (-1)#

The fact that the coefficient of #x# is #0# does not prevent this from being a quadratic function.

Aug 8, 2015

Any function containing the highest degree as #2# is quadratic. So:

#Ax^2 pm Bx pm C# is quadratic
where #A != 0# and #B# and #C# are anything real

#Ax^3 pm Bx^2 pm Cx pm D# is not (it's cubic)
where #A != 0# and #B#, #C#, and #D# are anything real