If the expression you are plotting uses the assignment operator (=), the equality relation operator (==), or more than 1 variable, use the fimplicit function instead of ezplot. Otherwise, use fplot instead of ezplot.

Both fplot and fimplicit require that the input function to plot is a function handle. The ezplot function accepted either a function handle or character vector.

For example, use fplot(@(x) sin(x.^2)) instead of ezplot('sin(x^2)') or fimplicit(@(x,y) sin(x)-cos(y)) instead of ezplot('sin(x)=cos(y)').