In the current market conditions it is impossible to double your capital with trading. Yes, in bull market doubling your capital will not be an issue. Many coins do 2x or more in that time. All you need to invest in few good altcoins and your money will be double in quick time. However in the current times, when bitcoin is not moving much, this is not possible.
Doubling your capital within 2 months is possible in any market conditions. It depends on how smart we are or how great our skills to do trading. Of course luck will also determine the result if we are dealing with altcoins that we do not know well. Not all altcoins is 100% depending on bitcoin movement, so it is still possible to find altcoins to make profit and double our capital.