2-how-to-find-the-domain-of-any-function-mathbff

# Interactive video lesson plan for: ❤︎² How to Find the Domain of Any Function (mathbff)

#### Activity overview:

MIT grad shows a surefire way to find the domain of any function. More videos with Nancy coming in 2017! To skip ahead: 1) For POLYNOMIAL only, skip to time 0:45. 2) For FRACTION only, skip to time 1:44. 3) For SQUARE ROOT only, skip to 5:08. 4) For SQUARE ROOT ON BOTTOM of Fraction, skip to 8:44. 5) For SQUARE ROOT ON TOP of Fraction, skip to 10:09.

For Domain, you just need to watch out for Square Roots and/or Fractions!

If your function is...

1) a POLYNOMIAL (no square roots or fractions), i.e. f(x) = x^2 + 3x + 1, domain is "all real numbers."

2) a FRACTION (w/ no square root), i.e. f(x) = (2x+1)/(x^2+5x+6). Set bottom "not equal" to zero. Solve for x.

3) a SQUARE ROOT (w/ no fraction), i.e. f(x) = sqrt(x+1). Set part under root "greater than or equal to zero".

4) a FRACTION w/ A SQUARE ROOT ON BOTTOM, i.e. f(x) = (x^2+2x+3)/(sqrt(x+1)). Set part under root "greater than zero." Solve the inequality. NOTE THE DIFFERENCE: You must set it greater than zero, not "greater than OR EQUAL TO zero" because we can't have zero (or square root of zero) in the denominator.

5) a FRACTION w/ A SQUARE ROOT ON TOP, i.e. f(x) = (sqrt(x+1))/(x^2+4), i) Set the bottom "not equal to" zero & solve; ii) Set what's under the root "greater than or equal to zero" & solve; iii) Take intersection of your two solutions.

Tagged under: domain function,domain,rational function,function,polynomial,quadratic expression,interval notation,set notation,square root,radical,fraction,infinity,trick,rules,explanation,equation,solve,solution,algorithm, find, ,algebra,algebra 2,precalculus,geometry,jmt,math,mathematics,-,khan,find,test,tutor,problem,linear,denominator,numerator,radicand,zeros,real numbers, real numbers, cases

Clip makes it super easy to turn any public video into a formative assessment activity in your classroom.

Add multiple choice quizzes, questions and browse hundreds of approved, video lesson ideas for Clip

Make YouTube one of your teaching aids - Works perfectly with lesson micro-teaching plans

Play this activity

1. Students enter a simple code

2. You play the video

3. The students comment

4. You review and reflect

* Whiteboard required for teacher-paced activities

## Ready to see what elsecan do?

With four apps, each designed around existing classroom activities, Spiral gives you the power to do formative assessment with anything you teach.

Quickfire

Carry out a quickfire formative assessment to see what the whole class is thinking

Discuss

Create interactive presentations to spark creativity in class

Team Up

Student teams can create and share collaborative presentations from linked devices

Clip

Turn any public video into a live chat with questions and quizzes

### 1000s of teachers use Spiral to deliver awesome, engaging activities that capture students' understanding during lessons.

Now it's your turn Sign up

### Spiral Reviews by Teachers and Digital Learning Coaches

@kklaster

Tried out the canvas response option on @SpiralEducation & it's so awesome! Add text or drawings AND annotate an image! #R10tech

@3rdgradeBCE

Using @SpiralEducation in class for math review. Student approved! Thumbs up! Thanks.

@ordmiss

Absolutely amazing collaboration from year 10 today. 100% engagement and constant smiles from all #lovetsla #spiral

@strykerstennis

Students show better Interpersonal Writing skills than Speaking via @SpiralEducation Great #data #langchat folks!

@iladylayla

A good tool for supporting active #learning.

@BrettErenberg

The Team Up app is unlike anything I have ever seen. You left NOTHING out! So impressed!

## Get the Clip Chrome Extension & Create Video Lessons in Seconds

Add Clip to Chrome