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How can polynomial long division be used to find the degree of the quotient?
Less than 5, see solution.
Let's start by recalling a few basic definitions.
Keeping all of these definitions in mind, let's move on to our task. Assume we are dividing a polynomial in one variable with a degree of 5 by a monomial in the same variable with a degree of 2. Let x be the variable. We can write the general form of our polynomial and monomial using letters to represent unknown coefficients.
| Polynomial | Monomial |
|---|---|
| 2x^5 | 3x^2 |
| 3x^5+2x^3-1 | x^2 |
| x^5+3x^4-7x^3-x^2+2x+8 | - 9x^2 |
We are interested in determining the degree of the result of the division. (ax^5+bx^4+xc^3+dx^2+ex+f)÷ gx^2 Let's calculate the first term of the quotient as we would do when using polynomial long division. This means we will divide the first term of the dividend by the first term of the divisor. ax^5/gx^2=a/gx^3 When using long division, the first calculated term of the quotient is always the one with the highest degree. Therefore, the degree of the quotient is 3 which is less than 5. Since we used the general form of the polynomial and the monomial, we can expect that the degree of the quotient will always be less than 5.
Write as a product of fractions
a^m/a^n= a^(m-n)
We can see that the degree of the term is m-n and therefore the degree of the quotient is m-n. Since the degree of a polynomial is non-negative, m-n is less than or equal to m. The degree of the quotient m-n is equal to m if and only if n=0. This is only when the divisor is a constant.