Can anyone help me how to know if the bitcoin price will decrease?
and how to trade bitcoins and earn? 
Because i invest bitcoins in yobit.net but i didn't know how to properly trade bitcoins. i will advice to make knowledge from best blogs about the trading and secondly you should subscribe some blogs amd sites for the bitcoin news and altcoin news they will gives approximate prediction of bitcoin and altcoin price due to start and stop of online market services .