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Monday, November 18, 2013

Polynomials


An expression with a single term is called as monomial, with two terms as binomial and with three terms as trinomial. If the number of terms is more, then such expressions are given a general name as polynomials, the word ‘poly’ means ‘many’. So it can also be written as poly-nomial to emphasize the meaning. Therefore, a poly-nomial is an expression that contains a number of terms consisting variables with constant coefficients. The terms of expression are usually arranged in descending order of the variable powers. Since a constant can also be expressed with the variable power as 0, a constant term can also be a part of a poly-nomial.
But as per convention in algebra, the definition of a polynomial includes certain restrictions. A polynomial can be built up with variables using all operations except division. For example, x3 – (2x + 3)/(x) + 7 cannot be called as a polynomial. However, this restriction applies only division by a variable and not for division by any constant, because such divisions can be considered as equivalent to fractional coefficients. The other restriction is that the exponents of the variables can only be non-negative integers.

A polynomial is generally an expression but acts as part both in equations and functions and such equations and functions are named with prefix ‘poly’ in general. In fact we convert a polynomial function to an equation while attempting to find its zeroes. Therefore, it is imperative to know how to factor a polynomial so that the zero product property can be used to determine the solutions. Using the zero product way is the easiest way to find the solutions of the variables.

Polynomial equations with a single variable with degrees 1 and 2 can easily be solved and the latter type is more popularly known as ‘quadratic’ equation. Mostly quadratic equations are possible to solve by factoring but even otherwise it can be done by using the quadratic formula. But equations with higher degrees are not all that easy to solve. But thanks to the great work by the mathematicians, there are ways to do that. Let us see some of the helpful concepts enunciated by the mathematicians.

As per fundamental theorem of algebra, the number of roots (the number of solutions of variables when equated to 0) of a polynomial is same as the degree of the same. This concept guides us to do the complete solution. We must also be aware that in some cases the solutions or some of the solutions may be imaginary. To get an idea on this, Descartes’s rule of sign changes helps. As per this rules we can figure out the number of real solutions, both positive and negative. Subsequently we can figure out the imaginary solutions with the help of fundamental theorem of algebra.

The rational zero theorem helps us to know what are the possible zeroes of a function. By a few trials, we can figure out a few zeroes and can reduce the polynomial to the level of a quadratic. Thereafter, the remaining zeroes can easily be figured out.

In addition, these days there are many websites advertising as ‘Factor Completely Calculator’ to help us in finding the solutions of a polynomial.

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