I have a polynomial function and I would like to find all the "x" values for a "y" value.
For example I have tried to plot this function:
I have tried to do all the intercepts with the interp1 formula (for example when y=600)
As you can see in the graph I should get 2 points when y=600 but I only one and it is the same for all the y values I use.
Please if you know any way to find all the interceptions when y=600 or any value it would be very helpful!
Thank you for your time and help.