hi

i have written the followin code that achieve Y from determinant of matric aa. but when i change digit my result changes. i dont know why? 

> restart;
> with(LinearAlgebra);
> Digits := 100;
>
> NULL;
> upsilon := .38;
> rho := 0.122e4;
> l := 0.176e-4;
> h := 2*0.176e-4;
> L := 20*h;
> NULL;
> E := 0.144e10;
> lambda := E*upsilon/((1+upsilon)*(1-2*upsilon));