To find the quotient of a polynomial division, you typically use polynomial long division, similar to the long division method used for numbers.
Steps for Polynomial Long Division:
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Arrange: Ensure both the dividend (the polynomial being divided) and the divisor (the polynomial you're dividing by) are written in descending order of exponents. Add placeholders (terms with a coefficient of 0) for any missing exponents. For example, if you have x3 + 1 being divided by x + 1, write the dividend as x3 + 0x2 + 0x + 1.
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Divide: Divide the first term of the dividend by the first term of the divisor. This will be the first term of the quotient.
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Multiply: Multiply the divisor by the term you just found in the quotient.
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Subtract: Subtract the result from the corresponding terms in the dividend.
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Bring Down: Bring down the next term from the dividend.
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Repeat: Repeat steps 2-5 using the new polynomial you created until the degree of the remaining polynomial (the remainder) is less than the degree of the divisor.
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Write the Result: The quotient is the polynomial you built in step 2. The remainder (if any) is the polynomial left after the final subtraction. Express the result as:
Dividend / Divisor = Quotient + Remainder / Divisor
Example:
Let's divide (x2 + 3x + 2) by (x + 1).
x + 2 | |
---|---|
x + 1 | x2 + 3x + 2 |
x2 + x | |
------- | --------- |
2x + 2 | |
2x + 2 | |
------- | --------- |
0 |
Explanation:
- Divide: x2 / x = x (This is the first term of the quotient)
- Multiply: x * (x + 1) = x2 + x
- Subtract: (x2 + 3x + 2) - (x2 + x) = 2x + 2
- Divide: 2x / x = 2 (This is the second term of the quotient)
- Multiply: 2 * (x + 1) = 2x + 2
- Subtract: (2x + 2) - (2x + 2) = 0 (Remainder)
Therefore, (x2 + 3x + 2) / (x + 1) = x + 2 + 0/(x+1) = x + 2.
Alternative Methods
- Synthetic Division: A shorthand method for polynomial division, but it only works when the divisor is of the form (x - a), where a is a constant.
Key Considerations:
- Be mindful of signs during the subtraction steps.
- Always ensure polynomials are arranged in descending order of exponents.
- If a term is missing in the dividend, add a placeholder with a coefficient of 0.