Why is my fplot not working?

My fplot is not working in my code. A few minutes ago, the code was plotting the graph just fine, but now it isn't. I can't figure out what is wrong. Matlab keeps saying that "Second argument must be a scalar or vector of unique symbolic variables."

%Symbolically find the roots of the following equation using 'solve'

syms x y(x)

y(x)=x^3+1

solve(x^3+1)

%Find what y equals when x=0

subs(y,x,0)

%Graph the equation on the interval [-10,10]

fplot(y,[-10,10],'b')

[Star Strider]

Your code works when I run it (R2019b).

Note that ‘y’ has three roots, two being complex:

syms x y(x)
y(x)=x^3+1
y0 = vpasolve(x^3+1)

figure
fplot(y,[-10,10],'b')

producing:

y0 =
                                      -1.0
 0.5 - 0.86602540378443864676372317075294i
 0.5 + 0.86602540378443864676372317075294i

and the figure.

[Kyle Donk]

Huh, it's working now. I guess I didn't exit my graph from the previous iterations of running my code, so it just kept the old graph instead of generating a new one.

[Star Strider]

That’s the reason I always use figure to create a new one for each plot. Otherwise, MATLAB uses the existing axes.