Update tutorial.rst
Update tutorial.rst

I did some elaborate math checking...
algernon/hy,larme/hy,zackmdavis/hy,tianon/hy,farhaven/hy,larme/hy,paultag/hy,freezas/hy,larme/hy,mtmiller/hy,tianon/hy,kirbyfan64/hy,jakirkham/hy,aisk/hy,hcarvalhoalves/hy,hcarvalhoalves/hy,tianon/hy,timmartin/hy,Foxboron/hy,kartikm/hy,michel-slm/hy,farhaven/hy,tuturto/hy,gilch/hy,Tritlo/hy,ALSchwalm/hy,aisk/hy,kirbyfan64/hy,farhaven/hy,adamfeuer/hy,aisk/hy,Foxboron/hy