How to find the two Y values for my function with one known X value? please help

Basically I'm having lots of trouble creating code that could give me the two y values that could coorespond to one x avlue i have.

My x value is 2. I have a function thats a circle that i stored and plotted like,

f=@(x,y)2*x*y - 6*y - 6*x + 4*x^2 + 6*y^2 - 12;

fimplicit(f)

I have two y values when x=2

I tried using the find function -----> index = find(x == 2)

but am only getting back one y value instead of two?

I search up all other examples on matlab answers but nothing is helping :(

[Star Strider]

When I run your code (after inserting the requisite multiplication operators, omitted in ‘f’), it plots a parabola.

[Katherine]

wow my mistake i pasted the wrong function. I edited the right one now

Answer 1

[John D'Errico]

There must be a million ways. Here is a trivial one.

f=@(x,y)2x*y - 6*y - 6*x + 4*x^2 + 6*y^2 - 12;
syms Y

Ysol = solve(f(2,Y))
Ysol =
  -1
 4/3

By the way, the function you showed had illegal syntax. You need to write 2*x, not 2x.

[Katherine]

Thanks John! would it be possible to have matlab simplify this number to a decimal instead of a fraction ?