First of all, consider the cubic equation $$x^3 + a = x. $$

Using Mathematica is easy to find real solutions of the above equation,

F[a_]:= Solve[x^3 + a == x , x, Reals]

Now, I would like to plot the graph of the multivalued function $$G: [-1,1]\to 2^\mathbb{R}$$ $$a \mapsto\ \{\text{the real solutions of }x^3 + a =x\}, $$ i.e. the set

$$\text{Graf}(G):= \{(x,y);\ x\in [-1,1]\ \text{and}\ y\in G(x)\}. $$

Can anyone help me?


1 Answer 1


Is this what you're looking for?

ContourPlot[x^3 + a == x, {a, -1, 1}, {x, -2, 2}, FrameLabel -> {a, x}]

enter image description here

  • $\begingroup$ You are right, I forgot about ContourPlot. Thx!!! $\endgroup$ Jul 27, 2019 at 21:53

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.