These past few days, I have learned how to determine what is the independent and dependent variable in a relation. I have also learned how to express an equation using table of values, ordered pairs, mapping diagram and graphs and how to state the domain and range.
To determine which is the independent variable and dependent variable, you must find out which is the input values and which are the output values.
Table of values always has the input values on the left side column and the output values are on the right side column. This means that the input values/numbers is the independent variables and the output values is the dependent variables. This goes the same for ordered pairs. The first number is the independent variable and the second number is the dependent variable. When looking at a graph, the x axis is the input values and the y axis is the output values.
When given an equation, at times you will have to find out what is x and y to be able to represent it in a table of values, a graph, or mapping diagrams.
For example, if you are given = y
If given the value of x and you are trying to find y, you must simply replace x with the input values.
Input values given: {-4, -3, -2, -1, 0, 1, 2, 3, 4}
= y
= 16-6 = 10
10 is one of the output values so when writing the ordered pair it would have x first then y second:
(-4, 10)
Do the same of each input value and write them in the table of values.
If given the value of y and you must find the value of x, you must get x by itself:
Output values: {-5, -3, 0, 2, 4, 6}
y = -x-2
-3 = -x-2
Add two to cancel out the two and add two to the -3 which gives you -1.
-1 = -x
Divide the -x by -1 to get x and divide -1 with -1 which gives you 1.
1 = x
Domain and Range
Domain is the set of all the possible values that’s used for the input of the independent variable and the range is the possible values used for the output of the dependent variables. When writing them, you must place them in ascending order meaning smallest to biggest. To find the domain, you must first look for the input values which is the numbers on the x axis. For range, it’s the output values on the y axis.
The hardest part so far of this lesson is finding the domain and range. I still struggle when I’m given diagrams that isn’t linear (meaning it’s a straight line) such as diagrams that is curved or has multiple lines instead of one straight line.