How to get better precision on nth roots than std::pow?

Asked Mar 26 '17 at 12:48

Active Mar 26 '17 at 12:48

Viewed 33 times

I've got to perform some mathematical operations which involve the 12th root of 2. The following two lines output the value 1.05946 to the console.

double x = pow (2.0, 1.0/12.0);
cout << x << endl;

I was expecting more significant figures. Is there a better way of getting a precise value (accurate to ~9 sf) for nth roots?

asked Mar 26 '17 at 12:48

Lammey

2

Someone will be along soon to explain about setprecision... – Paul R Mar 26 '17 at 12:51
1

Ah, got it. Cheers. – Lammey Mar 26 '17 at 12:57
1

You can get even more digits by computing `expm1(log(2)/12)` which will give you the `x` in `1+x=2^(1/12)` with 16 significant digits. – Lutz Lehmann Mar 26 '17 at 15:23

0 Answers0