Translating Functions Vertically and Horizontally
Horizontal Translation
- y = f(x - h)
- when x in a function is replaced with (x - h), it shifts that function h units horizontally
- if h is positive, shift right (in the positive x direction)
- if h is negative, shift left (in the negative x direction)
- when y = f(x) becomes y = f(x - h), (x, y) becomes (x + h, y)
e.g.
- y = f(x - 3) = f(x - (3)), h = 3, shift 3 units right
- y = f(x - 5) = f(x - (5)), h = 5, shift 5 units right
- y = f(x + 2) = f(x - (-2)), h = -2, shift 2 units left
- y = f(x + 1) = f(x - (-1)), h = -1, shift 1 unit left
Vertical Translation
- y = f(x) + k, or y - k = f(x)
- when k is added outside of f(x), it shifts that function k units vertically
- if k is positive, shift up (in the positive y direction)
- if k is negative, shift down (in the negative y direction)
- when y = f(x) becomes y = f(x) + k, (x, y) becomes (x, y + k)
e.g.
- y = f(x) + 4, k = 4, shift 4 units up
- y = f(x) - 2, k = -2, shift 2 units down
- y - 3 = f(x) can be written as y = f(x) + 3, k = 3, shift 3 units up
- y + 5 = f(x) can be written as y = f(x) - 5, k = -5, shift 5 units down
Combining Horizontal and Vertical Translations
- y = f(x - h) + k
- can be written as y - k = f(x - h)
- when y = f(x) becomes y = f(x - h) + k, (x, y) becomes (x + h, y + k)
Translating a Graph
- use the equation to recognize the transformations y = f(x - h) + k
- transform each point
- connect points
Finding a Translated Equation Example #1
- translated equation will have equation y = f(x - h) + k
- in any equation, replace x with (x - h), add k at the end
- use the transformations to find the values of h and k
- plug into equation
Finding a Translated Equation Example #2
Finding a Translated Equation Example #3
Finding the Equation of a Translated Graph
- choose one point on y = f(x) and find it's corresponding point on the translated graph
- find the horizontal and vertical shift between points to find the value of h and k
- plug into y = f(x - h) + k
How Asymptotes Change With Translations
- when a graph is shifted horizontally, the vertical asymptotes shift with it
- when a graph is shifted vertically, the horizontal asymptotes shift with it