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This educational guide provides a comprehensive overview of rationalizing denominators, focusing on the use of conjugates. You'll learn how to express fractions with irrational denominators as equivalent fractions with rational denominators through the multiplication of both numerator and denominator by a conjugate. Key concepts like rational and irrational numbers, perfect squares, and the importance of the identity element are explored. Several model problems demonstrate step-by-step processes for simplification and rationalization, enhancing your understanding of these essential algebraic techniques.
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Aim: How do we rationalize a denominator? Factor completely: 2x2 – 50 Do Now:
What is the conjugate of (x – 6) Conjugates 2x2 - 50 = 2(x – 5)(x + 5) conjugates of each other a2 – b2 = (a – b)(a + b) General Terms When conjugates are multiplied, the result is the difference between perfect squares. = x2 – 36 (x+ 6) = x2 – 5 = 9 – 7 = 2
Ex. 2, 1.765, 1/2, 0.33 Rational & Irrational Numbers Rational Numbers - Any number, integer, fraction, decimal; positive or negative, mixed or improper, that can be expressed as a fraction. Every rational number can be expressed as either a repeating or terminating decimal. Irrational Numbers - Any and all numbers that can not be expressed as a fraction. Ex. .439439543957. . . p = 3.1415926535897932 . . . = 1.4141213562 . . .
Real Number Family Rational Numbers Integers Irrational Numbers Whole Numbers Counting Numbers Irrational Numbers a/b Counting Numbers 1, 2, 3, 4, 5, . . . Whole Numbers 0, 1, 2, 3, 4, 5, . . Integers . . . -3, -2, -1, 0, 1, 2, 3, . . Rational Numbers a/b
rational number irrational number Rationalizing a Monomial Denominator means to remove the irrational number from the denominator Multiply fraction by a form of the identity element 1. Simplify the radical, if possible
a2 – b2 = (a – b)(a + b) How can we use the conjugate to rationalize Rationalizing a Denominator binomial denominator (of a fractionwhere the denominator is not a rational number) means to find a denominator in which the denominator is a rational number. Multiply fraction by a form of the identity element 1.
3 Model Problems Rationalize the denominator: Express as an equivalent fraction with a rational denominator. Write an equivalent expression for
Model Problems Simplify/Rationalize:
Model Problems Simplify/Rationalize:
Model Problems Simplify/Rationalize:
Model Problems Simplify/Rationalize:
Model Problems Simplify/Rationalize:
Model Problems Simplify/Rationalize: