I am using Mathematica 8.0.1.

I learned Mathematica by myself, and till yesterday I didn't need any feature of Mathematica

that is related with precision. But today I have to calculate some complicated formula... and the result should be

quite precise.

I knew that N[Pi, 40] gives the value of Pi upto 40 digits.

So we get 3.141592653589793238462643383279502884197

I wanted to get the value of 2^0.3, upto 40 digits. So I typed

N[2^0.3, 40]

But the result was not satisfactory. It just gave me

1.23114

Only 6 digits below the point.

I empirically know that if I copy a numerical value and paste it on a blank space in Mathematica

one can get better result.... I copied 1.23114 and paste in on a blank space then I get

1.2311444133449163`

But it too is far from 40 correct digits..

How can I get the precise value upto 40 digits ?

And what is the reason that N[2^0.3, 40] does not give 40 digits ?

Thank you very much!