Homework Help

The function `f(x)=x^2` . The graph of `g(x)` is `f(x)` translated to the left 5 units...

user profile pic

connorcolin3 | Valedictorian

Posted October 24, 2012 at 12:01 AM via web

dislike 2 like

The function `f(x)=x^2` . The graph of `g(x)` is `f(x)` translated to the left 5 units and down 3 units. What is the formula for `g(x)?`

2 Answers | Add Yours

user profile pic

degeneratecircle | High School Teacher | (Level 2) Associate Educator

Posted October 24, 2012 at 12:46 AM (Answer #1)

dislike 1 like

To translate any graph to the left 5 units, we replace `x` with `x+5,` giving `y=(x+5)^2.` Now, to shift this graph down 3 units, we subtract 3, getting

`g(x)=(x+5)^2-3.`

The way I thought about this when first learning was to shift the graph of `f(x)` to the left or right (in other words, horizontally), it makes sense that we should do something to the input, which is represented on the horizontal ` `axis. Thus, something like `f(x+5)` makes sense. To shift a graph up or down (vertically), we should do something to the output, which is just `f(x).` Thus, `f(x)-3` makes sense. Now if we combine the two we get

`g(x)=f(x+5)-3=(x+5)^2-3,` just as we got above. Here's the graph of  `y=(x+5)^2-3` in red and `y=x^2` in black.

 

Sources:

user profile pic

mmillar8537 | Student, Undergraduate | eNoter

Posted October 24, 2012 at 1:06 AM (Answer #2)

dislike 0 like

A good way to think about it for whenever you have to deal with it is:

g(x)=f(x-d)+c

Where d is a translation to the right or left

  • If d is positive it goes to the right (x-(d)) = (x-d)
  • If d is negative it goes to the left (x-(-d)) = (x+d)

and c is a translation up or down

  • If c is positive then it translates up
  • If c is negative then it translated down

Hope this helps you with your future work.

Join to answer this question

Join a community of thousands of dedicated teachers and students.

Join eNotes