Videos

Functions: How Can I Tell If a Relation is a Function?

Added Sep 08, 2020 •

Copy this URL:
Embed code:	<iframe class="edlio-embed-player" type="text/html" width="640" height="360" src="//shs.rcschools.net/apps/embed/?v=289953" frameborder="0" allowfullscreen></iframe> Change dimensions

The video reviews key vocabulary about relations essential to understand functions. Next, the video introduces three methods for sorting sets of ordered pairs, mapping diagrams and graphs into Function and Not a Function categories.

Show Transcript

today and integrated math 1 we are focused on functions are big question is how can I tell if I relationship is a function first some vocabulary about relations remember that our relation can be shown as a ordered pairs inner example we see a set of ordered pairs 2, 4/3, 6-4, a the domain is the set of all x-values or input values the rain is the set of all y output value what is the domain and range of the example shown are gel nails is 2 3 and 4 and arrange the Y values are for six and eight a function is a relation but if prefers to something very specific a function is a relation I have a set of inputs and outputs has exactly one output R function example set of ordered pairs access one why is 3x 4y 6 7 and Y is 9 notice for there is exactly one output cheers on not a function example look at this. ordered pairs x equals 1 has two different y values why can be three or why can B6 that is not a function let's compare these sets of ordered pairs on the left we have a set exercise for why is Chan where X is 5 Y is 9 and we're exes why is a is this a function we see that where X is 5 why is one we're X's 5y is to where X is 5y is 3 is this a function so let's compare these sets of ordered pairs by walking at the inputs with the outputs that way we can answer the question is this a function in our first set we see the X values are highlighted in green 456 imput has exactly one output set of ordered pairs we see x equals 5 highlighted in yellow where X is fine wine is one where X is 5 why is to wear answers 5 why is 3 the empress so which set is the function the first set is a function because what has exactly one output the set on the right is not a function for the input of five has multiple outputs mapping diagrams can help you find functions in this slide we're comparing two mapping diagrams the one on the left Smart Hub function look at the input and set a and the output in set B the input of five is paired with -2 as out infant -4 is paired with 2 as an output the input of six only goes to nine and the input of 4 only goes to -1 for each input there is only one output at the mapping diagram on the right noticed we highlighted the input value of 2 see how it goes to two different outputs and set B 8 5 only goes to -3 but for the input value of 2 we have multiple outputs is not a function when dealing with graphs the vertical line test is a helpful tool a vertical line is a line that goes up and we chatted X values for multiple outputs notice the vertical line that is drawn ax equals 6 where X is 6y can be one Nexus 6 it means that this is not a function let's compare graphs of functions with graphs of those that are not functions at the two graphs on the left you may recognize them as being part of function families the graph on the far left is a linear function notice it forms a straight line but what's most important to notice is that for each value of x there is only 1 values for y the next graph is a quadratic function we recognize it by its upside down you again for each value of x there is only one value of y the grass on the right are not functions imagine you're drawing a bird online let's look at the third graph if I draw a vertical line where x is 0 notice that why can be a positive 3 why can be a negative three again if we look at the last breath if I draw an up-and-down line a vertical line you can see for example if I do a line where X is -4 I would have two different values for why auctions now it's time for you to put your practice what you've learned today the work you will do will count bows as a practice so I can that's great and it will count as an assessment a quiz grade you will go online for your practice and Quest map each of you has a login you need to complete determine if a set of points is a function and determine if a graph is a function you need to get 10 problems correct in each group problems to be done please send me an email at shears at RCS schools.net if you have any questions or need assistance so we'll have office hours from noon until 12:30 each day you can arrange for me to call you to help you during that time send me an email to say I need help but I need to meet at some other time I will be sure to answer and Lissa happy practice is fun and the more you do it the better you will get

Uploaded by Suzanne Shearer.

Videos

Functions: How Can I Tell If a Relation is a Function?

More videos from Suzanne Shearer