Your best bet is studying something that you enjoy, regardless of whether it will be directly useful to LE. Your best bet is to do well in school and that is far more likely if you enjoy what you are studying.
It rarely matters what your degree is in, as long as you have a degree. Trust me, my degree is in molecular biology. You are a fool if you think I ever directly apply anything from my degree in my job. With that said, I think few would say that I am behind the powercurve. However, the methodology and problem-solving skills are useful in all aspects of life, generally and LE, specifically.
Now, to answer your question, I imagine (though, I am not qualified to speak to it), I imagine math would be fairly important in doing accident reconstructions. Some crime scene analysis would make great use of good math skills (trajectories of projectiles, blood splatter analysis, etc.).
I can tell you, first hand, that math can be useful in ranging out targets of unknown distance when you are a sniper. 
While there may be uses for strong math skills throughout LE, it will not be much more than freshman geometry. If you are looking for anything of particular challenging calculations, LE may not be your field.
We bring evil things to evil people, kicking in a door near you!
."In theory, there is no difference between theory and practice. But,
in practice, there is."
- Jan L.A. van de Snepscheut
"The difference between 'involvement' and 'commitment' is like
an eggs-and-ham breakfast: the chicken was 'involved' - the pig
was'committed'."
-unknown
Working on a PhD in CQB one doorway at a time.
When the wolf attacks, he will find not all who run with the flock are sheep!