Step by step
The question
Question: graph y = √−x + 1 from y = √x.
We know the graph of y = √x.
It is half a U, lying on its side.
1 Read the changes
The minus is inside, with x.
It changes the sign of every x.
Right becomes left.
So the graph flips over the y-axis.
Outside, at the end, + 1 adds 1 to every y.
So the graph moves up 1.
Careful!
A minus inside flips left and right.
A minus outside flips up and down.
2 Start from y = √x
Draw the grid.
Draw y = √x first.
It goes through (0, 0), (1, 1) and (4, 2).
3 Move the points
The start point (0, 0) moves up 1.
(0, 0) goes to (0, 1).
(1, 1) goes to (−1, 2).
(4, 2) goes to (−4, 3).
4 Draw the new graph
Join the new points with the same shape, flipped.
This is y = √−x + 1.
5 Check
Let's check.
Put x = 0 in the new rule.
We get y = 1: the point (0, 1) we drew.
And x = −4 gives y = 3: the point (−4, 3).
Let's look back.
First: read the changes.
Then: start from y = √x.
Then: move the points.
Then: draw the new graph.
Last: check.