Error when using ezplot

Hey, I'm trying to use ezplot to draw a plot with symbolic relations as follows:

and should draw with the range as following shows:

my code goes like follows:

syms x y t
x = 3*t/(1+t^3);
y = 3*t^2/(1+t^3);
a = x^3 + y^3 == 3*x*y
figure()
ezplot(a,[-2, 2, -3, 2])

but I got following erros:

Error using sym/ezplot>fhandle (line 115)
Two variables expected when plotting an equation.

Error in sym/ezplot (line 78)
      h = ezplot(fhandle(f),varargin{:});%#ok<EZPLT>

Error in test10 (line 13)
ezplot(a,[-2, 2, -3, 2])

what's wrong with the code?

Answer 1

[Stephan]

syms a(x,y)
a = x^3 + y^3 - 3*x*y == 0;
ezplot(lhs(a),[-2, 2, -3, 2])

[kairui wang]

Thanks. You reminds me that I don't need to care about t.

[madhan ravi]

thought of it too but the relationship with t makes it confusing [t = -1 doesn't belong to the domain]