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

Complete and Continue