How to find EF and IUF? For example , giving u(x,y)= X1/2*Y1/2, m=32px=1py=1 the formula of finding iuf is v=m/4pxpy, and for EF is m=v4pxpy but in another example, giving u(x,y)=Min(x,2y),m=15,px=1,py=1 the formula of finding iuf is using v=2m/2px+2py, and EF is m=v(2px+2py)/2 How do I use the iuf and EF in different situation, or is there a formula to calculate or like when to using iuf and EF under different situation? Or how should I know what is the right iuf and EF formula to use in different situation thx