Math pow returns 1.0

Question

I am very new in java dev so it might be a trivial question:

double u130 = (1 / 30);
double q1 = Math.pow(1.025, u130);

the q1 is equal 1.0, but it should be 1.0008234259155

u130 = 0.0 also wrong.

I my understanding double is made for so many decimal places, so where is the problem?

By the way I am testing on Android device, this should be a limitation?!

Thanks

rom1v · Accepted Answer · 2017-01-21T16:49:14.927

5

1 / 30 is the euclidian division, so the result is 0 (as int).

Instead, you need a real division:

double u130 = 1. / 30;
double q1 = Math.pow(1.025, u130);

edited Jan 21 '17 at 16:49

answered Jan 21 '17 at 16:47

rom1v

1

`1.0` instead of `1.` – Null Jan 21 '17 at 16:48
`1.` is sufficient. – rom1v Jan 21 '17 at 16:49
1

i never test it before, its good to know new things, :)) – Null Jan 21 '17 at 16:50
`1.` is barely legible and kind of hides the fact it's a `double`. – Olivier Grégoire Jan 21 '17 at 16:52

score 0 · Answer 2 · answered Jan 21 '17 at 16:51

0

This should solve your problem :

    double u130 = (1 / (double)30);
    double q1 = Math.pow(1.025, u130);

answered Jan 21 '17 at 16:51

OBX

2 Answers2