Polynomials

Variables and polynomial:

Polynomial of zero variable

If a polynomial has no variable, it is called polynomial of zero variable. For example – 5. This polynomial has only one term, which is constant.

Polynomial of one variable

Polynomial with only one variable is called Polynomial of one variable.

Example: `5x+2, 2x^2+x+3`, etc.

In the given example polynomials have only one variable i.e. x, and hence it is a polynomial of one variable.

Polynomial of two variables

Polynomial with two variables is known as Polynomial of two variables.

Example: `5x+y, 2x+3y+2`, etc.

In the given examples polynomials have two variables, i.e. x and y, and hence are called polynomial of two variables.

Polynomial of three variables

Polynomial with three variables is known as Polynomial of three variables.

Example: `2x^2+3y+m+2` and `5y+3m+z+5`

In the above examples polynomials have three variables, and thus are called Polynomials of three variables.

In similar way a polynomial can have of four, five, six, …. etc. variables and thus are named as per the number of variables.

Degree of Polynomials:

Highest exponent of a polynomial decides its degree.

Polynomial of 1 degree:

Example: `2x + 1`
In this since, variable x has power 1, i.e. x has coefficient equal to 1 and hence is called polynomial of one degree.

Polynomial of 2 degree

Example: `2x^2+2x+2`

In this expression, exponent of x in the first term is 2, and exponent of x in second term is 1, and thus, this is a polynomial of two(2) degree.

To decide the degree of a polynomial having same variable, the highest exponent of variable is taken into consideration.
Similarly, if variable of a polynomial has exponent equal to 3 or 4, that is called polynomial of 3 degree or polynomial of 4 degree respectively.

Important points about Polynomials:

• A polynomial can have many terms but not infinite terms.
• Exponent of a variable of a polynomial cannot be negative. This means, a variable with power - 2, -3, -4, etc. is not allowed. If power of a variable in an algebraic expression is negative, then that cannot be considered a polynomial.
• The exponent of a variable of a polynomial must be a whole number.
• Exponent of a variable of a polynomial cannot be fraction. This means, a variable with power 1/2, 3/2, etc. is not allowed. If power of a variable in an algebraic expression is in fraction, then that cannot be considered a polynomial.
• Polynomial with only constant term is called constant polynomial.
• The degree of a non-zero constant polynomial is zero.
• Degree of a zero polynomial is not defined.