The degree of a polynomial function equation is the highest power of the variable in the polynomial.
To understand this, let's break it down:
-
Polynomial Function: An expression containing variables and coefficients, involving only the operations of addition, subtraction, multiplication, and non-negative integer exponents of variables.
-
Term: A single part of the polynomial separated by addition or subtraction. For example, in the polynomial
3x^2 + 2x - 5
,3x^2
,2x
, and-5
are terms. -
Degree of a Term: The sum of the exponents of the variables in that term. For example:
- The degree of
3x^2
is 2. - The degree of
2x
(which is2x^1
) is 1. - The degree of
-5
(which is-5x^0
) is 0. - The degree of
4x^3y^2
is 3 + 2 = 5.
- The degree of
-
Degree of the Polynomial: The highest degree of any term in the polynomial.
Examples:
-
f(x) = 5x^3 - 2x + 1
: The highest power ofx
is 3, so the degree is 3. -
g(x) = x - 7
: The highest power ofx
is 1 (sincex = x^1
), so the degree is 1. This is also known as a linear function. -
h(x) = 9
: This can be written ash(x) = 9x^0
. The degree is 0. This is a constant function. -
k(x) = 2x^4 - x^2 + 3x^5 - 7
: The highest power ofx
is 5, so the degree is 5. (Note that the terms don't have to be written in descending order of exponents). -
l(x, y) = 3x^2y + 5xy^3 - x + 2y - 8
: The term5xy^3
has degree 1 + 3 = 4, which is the highest among all terms, so the degree is 4.
Key Points:
- The degree of a polynomial is always a non-negative integer.
- The degree of a polynomial tells you something about the function's behavior, particularly its end behavior (what happens to the function as x approaches positive or negative infinity).
In summary, the degree of a polynomial function is determined by the highest exponent of its variable(s) after the polynomial has been simplified.