Intermediate Algebra – Student Workbook – Second Edition 2013

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Date: ________________
Mini-Lesson 6b
Rational/Radical Roots
SQUARE ROOTS
The square root of a is written as a . If a = b then b2 = a.
NOTATION:
1
The notation a , is RADICAL NOTATION for the square root of a. The notation a 2
is
RATIONAL NOTATION for the square root of a.
On your TI 83/84 calculator, you can use the
symbol to compute square roots.
EXAMPLES:
a) 25 = 5 because 5 2 = 25
b) ( 144) 2 =144 (Note that the square and square root “undo” each other)
(c) 25 1 2 = 25 = 5
(e) 1 2
64 is not a real number because there is no number, squared, that will give -64
CUBE ROOTS
The cube root of a is written as
3
a
3
. If a = b then b3 = a.
NOTATION:
1
3
The notation a , is RADICAL NOTATION for the cubed root of a. The notation a 3
is
RATIONAL NOTATION for the cubed root of a.
EXAMPLES:
3
a) 81 = 9 because 9 3 = 81
3
3
b) 64 4 because (-4) 64
Note that cube roots can be negative.
On your TI 83/84 calculator, you can use the MATH>4: 3
roots.
( sequence to compute cube
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