Simplifying Radicals

Simplifying Radicals
Unit 10 Lesson 2
Simplifying Radicals
Students will be able to:
β€’ Use square root and cube root symbols to represent
solutions to equations of the form 𝒙 𝟐 = 𝒑 and 𝒙 πŸ‘ = 𝒑,
where p is a positive rational number
β€’
Simplify expressions involving radicals using the
properties of radicals.
Simplifying Radicals
Key Vocabulary:
β€’ Radical
β€’ Radicand
β€’ Simplifying Radicals
β€’ Denominator
β€’ Like Radicals
Simplifying Radicals
Radicals (or roots) are the opposite operation of applying
exponents.
A power can be undone with a radical and a radical can be
undone with a power.
𝟐
β€’ 𝟐 = πŸ’ 𝒔𝒐
πŸ‘
β€’ 𝟐 = πŸ– 𝒔𝒐
πŸ’=𝟐
πŸ‘
πŸ–=𝟐
π’Šπ’π’…π’†π’™
π’“π’‚π’…π’Šπ’„π’‚π’π’…
Radical sign
Simplifying Radicals
Common Radicals:
β€’ A square (second) root is written as √
β€’ A cube (third) root is written as βˆ›
β€’ A fourth root is written as ∜
Simplifying Radicals
β€’ To simplify a radical, factor the expression under
the radical sign to its prime factors.
β€’ For every pair of like factors, bring out one of the
factors.
β€’ Multiply whatever is outside the sign, and then
multiply whatever is inside the sign.
β€’ Remember that for each pair, you β€œbring out”
only one of the numbers.
Simplifying Radicals
β€’ Variables in a radicand are simplified in the same way. You've got
a pair of can be taken "out front".
β€’ Negative Radicals
The only restriction that exists for negative signs and radicals is that
there cannot be a negative sign under an even root since there is no
real solution to this problem.
However, a negative sign can exist in front of a radical or under odd
roots and still be able to obtain a real number.
Simplifying Radicals
β€’ PRODUCT RULE FOR RADICAL
The radical of the product is the product of two
radicals.
π’Ž
π’™π’š =
π’Ž
π’™βˆ—π’Ž π’š
Simplifying Radicals
QUOTIENT RULE FOR RADICAL
The radical of a quotient is the quotient of the radicals.
π’Ž
𝒙
=
π’š
π’Ž
π’Ž
𝒙
π’š
π’šβ‰ πŸŽ
Simplifying Radicals
Sample Problem 1: Simplify the following expressions.
Assume that all variables represent positive real numbers.
𝒂. 𝟐𝟎 =
𝒃. πŸ•πŸπ’‚πŸ =
𝐜. πŸ’πŸ“ =
Simplifying Radicals
Sample Problem 1: Simplify the following expressions.
Assume that all variables represent positive real numbers.
𝒂.
𝟐𝟎 = πŸ’ βˆ— πŸ“ =
𝒃. πŸ•πŸπ’‚πŸ =
𝐜. πŸ’πŸ“ =
𝟐𝟐 βˆ— πŸ“ = 𝟐 πŸ“
𝟐 βˆ— πŸ‘πŸ” βˆ— π’‚πŸ = 𝟐 βˆ— πŸ”πŸ βˆ— π’‚πŸ = πŸ”π’‚ 𝟐
πŸ‘πŸ βˆ— πŸ“ =
πŸ‘πŸ βˆ— πŸ“ = πŸ‘ πŸ“
Simplifying Radicals
Sample Problem 1: Simplify the following radicals. Assume that all
variables represent positive real numbers.
πŸπŸ’
πŸ“πŸ’
d.
e.
f.
πŸ“
πŸ‘
=
βˆ’πŸ‘πŸπ’šπŸ“
π’™πŸπŸŽ
π’™π’›πŸ’
π’šπŸ”
=
=
Simplifying Radicals
Sample Problem 1:
Simplify the following radicals. Assume that all variables represent
positive real numbers.
πŸπŸ’
πŸ“πŸ’
d.
e.
f.
πŸ“
πŸ‘
=
πŸπŸ’
πŸ“πŸ’
π’™π’›πŸ’
π’šπŸ”
=
=
πŸ“
βˆ’πŸ‘πŸπ’šπŸ“
π’™πŸπŸŽ
πŸ’βˆ—πŸ”
πŸ—βˆ—πŸ”
=
πŸ“
πŸ‘
π’™π’›πŸ’
πŸ‘
π’šπŸ”
=
βˆ’πŸ πŸ“ βˆ—π’šπŸ“
πŸ“
π’™πŸ“ βˆ— π’™πŸ“
πŸ‘
=
𝟐𝟐
πŸ‘πŸ
=±
βˆ’πŸπ’š
π’™πŸ
=
πŸ‘
π’™βˆ— πŸ‘ 𝒛 βˆ— π’›πŸ‘
πŸ‘
πŸ‘
π’šπŸ‘ βˆ—
𝟐
πŸ‘
π’šπŸ‘
=
𝒛 πŸ‘ 𝒙𝒛
π’šπŸ
Simplifying Radicals
β€’ Radicals can also be written in exponent notation.
However, in this case the exponent would be a fraction.
𝒏
π’Ž
π’Ž
𝒙𝒏 = 𝒙
𝒏
𝒙𝒏 = 𝒙
β€’ If 𝑛 is odd then
β€’ If 𝑛 is even then
𝒏
𝒙𝒏 = 𝒙
Simplifying Radicals
Sample Problem 2:
Write each expression in radical notation.
a. πŸ’
𝟏
𝟐
=
b. βˆ’πŸ–
𝟏
πŸ‘
c. πŸ’ =
𝟏
πŸ‘
=
Simplifying Radicals
Sample Problem 2:
Write each expression in radical notation.
a. πŸ’
𝟏
𝟐
b. βˆ’πŸ–
𝟏
πŸ‘
c. πŸ’ =
= πŸ’ = ±πŸ
𝟏
πŸ‘
πŸ‘
=
πŸ’
πŸ‘
βˆ’πŸ– =
πŸ‘
βˆ’πŸ
πŸ‘
= βˆ’πŸ
Simplifying Radicals
Sample Problem 3:
Write each expression in exponential notation.
a.
b.
πŸ‘
πŸ“
πŸ’
βˆ’πŸ”πŸ’ =
πŸ‘πŸ =
c. πŸ”πŸπŸ“ =
Simplifying Radicals
Sample Problem 2:
Write each expression in exponential notation.
a.
πŸ‘
βˆ’πŸ”πŸ’ = βˆ’πŸ”πŸ’
πŸ“
𝟏
πŸ“βˆ— πŸ“
πŸ’
πŸ’
b. πŸ‘πŸ = 𝟐
c. πŸ”πŸπŸ“ =
𝟏
πŸ‘
𝟏
= βˆ’πŸ’
=𝟐
πŸ’
πŸ’
πŸ“πŸ’ = ±πŸ“ = ±πŸ“
πŸ‘βˆ—πŸ‘
= βˆ’πŸ’
Simplifying Radicals
RATIONALIZING THE DENOMINATOR
When dealing with fractions, a final answer cannot
contain radicals in the denominator.
Therefore, it is necessary to eliminate any radical
from the denominator.
The process of removing the radical from the
denominator is called rationalizing the
denominator.
Simplifying Radicals
Rationalizing the denominator
1. An expression is considered simplified only if there is no radical sign in the
denominator.
𝟏
𝒏
π’™π’Ž
=
𝟏
𝒏
π’™π’Ž
𝒏
βˆ—π’
π’™π’βˆ’π’Ž
π’™π’βˆ’π’Ž
𝒏
=
π’™π’βˆ’π’Ž
𝒙
2. Rationalizing the denominator with two terms, one or both of which involve
square root.
Step 1: Multiply the numerator and denominator by the conjugate of the denominator
Step 2: Simplify the resulting expression if possible
Simplifying Radicals
Sample Problem 4:
Simplify the following expressions. Assume that all variables
represent positive real numbers.
a.
b.
7
5
=
2
π‘₯+𝑦
=
Simplifying Radicals
Sample Problem 4:
Simplify the following expressions. Assume that all variables
represent positive real numbers.
a.
b.
πŸ•
πŸ“
=
𝟐
𝒙+π’š
πŸ•
πŸ“
βˆ—
=
πŸ“
πŸ“
=
𝟐
𝒙+π’š
πŸ• πŸ“
πŸ“
βˆ—
𝒙+π’š
𝒙+π’š
=
𝟐
𝒙+π’š
𝒙+π’š
Simplifying Radicals
Sample Problem 4:
Simplify the following expressions. Assume that all variables
represent positive real numbers.
c.
d.
𝟐
πŸβˆ’ πŸ”
𝒙
πŸβˆ’ 𝒙
=
=
Simplifying Radicals
Sample Problem 4:
Simplify the following expressions. Assume that all variables
represent positive real numbers.
c.
𝟐
πŸβˆ’ πŸ”
𝒙
d.
πŸβˆ’ 𝒙
=
𝟐
πŸβˆ’ πŸ”
=
𝒙
πŸβˆ’ 𝒙
βˆ—
𝟐+ πŸ”
𝟐+ πŸ”
βˆ—
𝟏+ 𝒙
𝟏+ 𝒙
=
=
𝟐 𝟐+ πŸ”
𝟐𝟐 βˆ’
πŸ”
𝟐
𝒙 𝟏+ 𝒙
𝟏𝟐 βˆ’
𝒙
𝟐
=
=
𝟐 𝟐+ πŸ”
βˆ’πŸ
𝒙 𝟏+ 𝒙
πŸβˆ’π’™
=βˆ’ 𝟐+ πŸ”
Simplifying Radicals
β€’ POWER OF A RADICAL
The radicand has to be raised to the exponent of the power while
the index remains the same.
π’Ž
𝒙𝒏
𝒑
=
π’Ž
π’™π’βˆ—π’‘
Simplifying Radicals
β€’ RADICAL OF A RADICAL
The radicand stays the same, and the index is the product of the
indices.
π’Ž 𝒏
𝒙 =
π’Žβˆ—π’
𝒙
Simplifying Radicals
Sample Problem 5: Simplify the following expressions. Assume that
all variables represent positive real numbers.
πŸ“
a.
πŸ‘
b.
πŸπŸπŸ“
𝟐
π’™πŸ“ =
=
Simplifying Radicals
Sample Problem 5: Simplify the following expressions.
Assume that all variables represent positive real numbers.
πŸ“
a.
πŸ‘
b.
πŸπŸπŸ“
π’™πŸ“
𝟐
=
=
πŸ‘βˆ—πŸ
πŸ“
πŸ“πŸ‘βˆ—πŸ
π’™πŸ“
=
=
πŸ”
πŸ“
π’™πŸ“
πŸ“πŸ”
πŸ“
=πŸ“ πŸ“
Simplifying Radicals
Like radicals are radicals that have the
same index and the same radicand
Simplifying Radicals
Sample Problem 6:
Simplify radicals and recognize like or unlike radicals.
a. 𝟐 πŸ“ 𝐚𝐧𝐝 πŸ‘ πŸ“
b.
πŸπŸπŸ“ ;
πŸ‘ πŸ–πŸŽ
𝐚𝐧𝐝
πŸ’πŸ“
Simplifying Radicals
Sample Problem 6:
Simplify radicals and recognize like or unlike radicals.
𝐚. 𝟐 πŸ“ 𝒂𝒏𝒅 πŸ‘ πŸ“
𝑳𝑰𝑲𝑬 𝑹𝑨𝑫𝑰π‘ͺ𝑨𝑳𝑺
b. πŸπŸπŸ“ ; πŸ‘ πŸ–πŸŽ
𝒂𝒏𝒅 πŸ’πŸ“
πŸπŸ“ βˆ— πŸ“; πŸ‘ πŸπŸ” βˆ— πŸ“; 𝒂𝒏𝒅 πŸ— βˆ— πŸ“
πŸ“ πŸ“;
𝟏𝟐 πŸ“;
𝒂𝒏𝒅 πŸ‘ πŸ“
𝑳𝑰𝑲𝑬 𝑹𝑨𝑫𝑰π‘ͺ𝑨𝑳𝑺
Simplifying Radicals
Sample Problem 6:
Simplify radicals and recognize like or unlike radicals.
πŸ‘
c. πŸ’ π’™πŸ 𝒂𝒏𝒅 πŸ’ π’™πŸ‘
d. πŸ‘ π’‚π’ƒπŸ ;
πŸ’π’ƒ 𝒂;
πŸ’π’‚π’ƒπŸ
Simplifying Radicals
Sample Problem 6:
Simplify radicals and recognize like or unlike radicals.
πŸ‘
c. πŸ’ π’™πŸ 𝒂𝒏𝒅 πŸ’ π’™πŸ‘
𝑼𝑡𝑳𝑰𝑲𝑬 𝑹𝑨𝑫𝑰π‘ͺ𝑨𝑳𝑺
d. πŸ‘ π’‚π’ƒπŸ ; πŸ’π’ƒ 𝒂;
πŸ’π’‚π’ƒπŸ
πŸ‘π’ƒ 𝒂 ; πŸ’π’ƒ 𝒂; πŸπ’ƒ 𝒂
𝑳𝑰𝑲𝑬 𝑹𝑨𝑫𝑰π‘ͺ𝑨𝑳𝑺