How do you graph y=sqrt(x-3)+2 and how does it compare to the parent function?

1 Answer
Jun 13, 2018

See below

Explanation:

The second question answer the first, I'd say. Let's see the effect of the transformations: given a parent function f(x), we have four basic transformation: stretched and translation, both horizontal and vertical.

  • Vertical stretch: we obtain it by multipling the whole function by some constant, so f(x) \to kf(x). If 0<k<1 we have a vertical shrink, if k>1 we have a vertical expansion. If k is negative the function is reflected about the x axis, and then stretched as above.
  • Horizontal stretch: we obtain it by multiplying the variable by some constant, so f(x) \to f(kx). If 0<k<1 we have a horizontal expansion, if k>1 we have a horizontal shrink. If k is negative the function is reflected about the y axis, and then stretched as above.
  • Vertical translation: we obtain it by adding some constant to the function, so f(x)\to f(x)+k. If k is positive the shift is upwards, otherwise it's downwards.
  • Horizontal translation: we obtain it by adding some constant to the variable, so f(x)\to f(x+k). If k is positive the shift is leftwards, otherwise it's rightwards.

In your case, you have both vertical and horizontal translation, so you have

sqrt(x) \to sqrt(x-3) \to sqrt(x-3)+2

The first transformation translates the function three units to the right, the second one two units higher. See the graph of the three steps to check:

Parent function: y=sqrt(x)
graph{sqrt(x) [-3.5, 10, -0.5, 5]}

First translation: y = sqrt(x-3)
graph{sqrt(x-3) [-3.5, 10, -0.5, 5]}

Second translation: y = sqrt(x-3)+2
graph{sqrt(x-3)+2 [-3.5, 10, -0.5, 5]}