2. What is a Square Root?
The opposite of squaring a number.
r is the square root of s if r2 = s
Positive numbers have two square roots:
and –
is called a radical sign
The number inside is the radicand
The expression is a radical
3. Properties of Square Roots
Product Property:
Example:
Used to simplify radical expressions.
4. Simplifying Radical Expressions
Using the Product Property:
1. Try to find a “perfect square” that is a factor.
2. Rewrite as a product of two radicals.
3. Take the square root of the perfect square.
Example: Simplify
8. Simplifying Radical Expressions
Using the Quotient Property:
1. Rewrite as a quotient of two radicals.
We can’t leave a square root on the bottom!
If bottom is a perfect square:
1. Take square roots on top and bottom.
2. Simplify the top if needed.
If bottom is not a perfect square:
1. Multiply by the denominator over itself.
2. Simplify.
◦ Called “Rationalizing the Denominator”
11. Solving Equations
Square roots can be used to solve some
quadratic equations.
For example: has two solutions,
Usually written
is read “plus or minus”
14. Using Quadratic Models
On Earth, when an object is dropped, its
height h (in feet), t seconds after being
dropped, can be modeled by:
where is the object’s initial height
(note: this model neglects air resistance)
15. Example:
How long will it take an object dropped
from a 550-foot tall tower to land on the
roof of a 233-foot tall building?