Hi all,

I see this equation and I want to plot it, but could not be able to do it:

z^{3} - z = (x^{3} - x) + (y^{3} - y)

This is my code:

```
using Plots
pyplot()
x=range(-2,stop=2,length=100)
y=range(sqrt(2),stop=2,length=100)
my_cg = cgrad([:green,:blue])
f(x,y) = ((x^(3) - x) + (y^(3) - y))^(0.5)
plot(x,y,f,st=:surface,c=my_cg,camera=(-30,30))
```

There is an error:

**DomainError with -4.585786437626904:**

**Exponentiation yielding a complex result requires a complex argument.**

**Replace x^y with (x+0im)^y, Complex(x)^y, or similar.**

Is the solutions involving complex numbers?

I choose to use f(x,y) first instead of the z^3 - z because it will be more difficult.