How to draw the image of implicit function x ^ 4 + y ^ 2 = 1 with MATLAB?

How to draw the image of implicit function x ^ 4 + y ^ 2 = 1 with MATLAB?

ezplot( 'x.^4+y.^2-1' ,[-2,2]) 
Just use this ezplot, where 1 is moved to the left of the equal sign
As shown in the figure: