When i am running your code for following equations,roots are not correct .Kindly help me.
f1(x,y) = '(((1+2*x^2)/(1-x^2))+(4*(1-2*y^2)*sqrt(1-x^2)*(2+x^2))/((1-x^2)*(1-y^2)^0.5*(2+y^2)))'

i keep getting this message.
!Error using diff
Difference order N must be a positive integer scalar.
Error in newton3v1 (line 35)
gradf1 = [diff(f1name,'x') diff(f1name,'y') diff(f1name,'z')];!