How To

[andieje]

Hi

I'm trying to plot the function x = 9 - y^2 with x as the horizontal axis by typing "plot x = 9 - y^2" but it automatically puts x as the vertical and y as the horizontal axis. Do i have to re-write the function with y as the subject? Presumably there is a command to get wolfram alpha to rewrite this for me with y as the subject. Hopefully there is a command i can add to force WA to keep x as the horizontal axis

thanks

[briangilbert]

Plot x = 9 - y^2 for y

[andieje]

many thanks

[andieje]

Hi

Are you still there? I just assumed that would work but it didn't. It still plotted y as the horizontal axis instead of keeping x as the horizontal axis

thanks

[briangilbert]

Hi

Are you still there? I just assumed that would work but it didn't. It still plotted y as the horizontal axis instead of keeping x as the horizontal axis

thanks

Sorry about that. I am only fishing.
How about solving your equation for y, using Solve x=9-y^2
Giving plus or minus Sqare root (9-x)
Click on the answer to get the plain text.
Copy and paste the plaintext answer into a new input line.
Put 'Plot Y=' in front and remove the plus/minus sign.
giving your input as
Plot y = sqrt(9-x)
That gives an interesting result but is it what you are after?

[andieje]

Hi

That doesn't really work because in the plot x = 9-y^2 you get the points (0,3) and (0,-3)

If you plot y = (9-x)^1/2 then you only get (0,3)

thanks

[briangilbert]

You seem to be satisfied with the original graph except that you want the x and the y axes interchanged.

Input the original graph into a picture editing program such as MS Paint. Rotate the image 90 degrees clockwise, and then flip it top to bottom.