I would like to evaluate the expression $f(x) = \sqrt{x+2} -\sqrt{x}$ with cases when $x = 3.2 \times 10^{30}$ and $x= 3.2 \times 10^{16}$. I tried using N[Sqrt[x+2] - Sqrt[x], 100]
and
ScientificForm[Sqrt[x+2] - Sqrt[x], 100]
, both yielding 0 as an output. How can I obtain the desired output?
I also tried the method in Making a calculation with high precision by applying .`100
as a suffix but my mathematica 12 doesn't seem to be recognizing it.