Week 4 – Addition, Subtraction, Multiplication and Division of Radicals

In Grade 9, we looked at the concept of grouping like terms.

Grade 9; 5x + 6y – 3x + 9y + x

x = 3x

y= 15y

Now in Grade 11, we now group radicals.

Grade 11; 4\sqrt[3]{9}, 6\sqrt[3]{9}, 15\sqrt[3]{9}

= 25\sqrt[3]{9}.

Rule

Radicand and index must be the same.

Subtraction

\sqrt{160}\sqrt{40}

= \sqrt{16\cdot10}\sqrt{4\cdot10}

= 4\sqrt{10} – 2\sqrt{10}

= 2\sqrt{10}

 

Division and Multiplication Rule

The denominator CANNOT be a radical

 

Rationalizing the Denominator

\sqrt{5} /    x    \sqrt{6}\sqrt{30} /   ——->       \sqrt{30} /

\sqrt{6}       x    \sqrt{6}\sqrt{36}      ——->        6

 

Rationalizing the denominator is a way of cancelling out the radical so the denominator is not a radical.

1.) Recognize that the denominator is a radical

2.) Multiply both the numerator and the denominator (what you do the bottom you got to do the top)

3.) Simplify to find the new values

4.) See if there are any perfect squares (if the index is for example 3, then look for perfect cubes)

5.)Simplify the new values

6.) MAKE SURE A RADICAL IS NOT IN THE DENOMINATOR PLACE.

Week 3 – Absolute Value, Roots

This week we learned some new concepts and reviewed concepts from grade 10.

2.1 Absolute Value – The principal square root of the square root of a number.

ex. \mid{-7}\mid      absolute value = 7

the absolute value is the amount that the given number is different from 0.

Note – The radicand can only be positive

\mid{7-16}\mid

7 – 16 = -23

absolute value = 23

-23 & 23, are both 23 digits away from 0.

2.2 Roots and Radicals

Perfect Squares 4,9,16,25,36,49,64,81,100

Perfect Cubes 8,27,64,125

Simplify

\sqrt [3]{40}

=\sqrt[3]{8\cdot5}

=2\sqrt[3]{5}