How do you sketch the graph of #y=-(x+2)^2+2 and describe the transformation?

1 Answer
Dec 17, 2017

The transformations are: shift two units to the left (horizontal shift), reflect over the x-axis, shift two units up (vertical shift)

Explanation:

Begin with the graph of the parent function: y=x^2
graph{x^2 [-10, 10, -5, 5]}
Now we want to deal with each of the transformations one at a time.

Looking at y=-(x+2)^2+2 the first transformation is to shift the graph 2 units to the left because of the x+2 in parentheses.

That gives us this graph:
graph{(x+2)^2 [-10, 10, -5, 5]}
The vertex moved from (0,0) to (-2,0) with that transformation.

Looking back at our function, y=-(x+2)^2+2, the next transformation to deal with is that negative. That will cause our graph to reflect over the x-axis. The vertex doesn't change with this transformation.

Now the graph looks like:
graph{-(x+2)^2 [-10, 10, -5, 5]}

Finally we want to deal with the +2 at the end of the function. That will take the entire graph and shift it two units up (vertically). This changes the vertex to (-2,2).

Here's the final graph:

graph{-(x+2)^2+2 [-10, 10, -5, 5]}

So the transformations are: shift two units to the left (horizontal shift), reflect over the x-axis, shift two units up (vertical shift).