Compiling any formulas for determining the price of bitcoin or any other decentralized cryptocurrency will be deliberately erroneous. Such a formula simply does not exist and cannot exist. The price of a decentralized cryptocurrency completely depends on the ratio of supply and demand in the market. These factors cannot be predictable. The actual price of the cryptocurrency is only the one that exists at the moment. In a moment, the real price for it will already be different.
There were no prediction which were made in last one and half years have even reached closer to how the market has been and it will be foolishness to depend of predictions or analysis because we know very well those days are gone when it used to work but since there are too many big players involved in the bitcoin market we cannot predict how they can alter the demand and supply according to their plan which will affect the entire market and we are small fish trying to get benefited by these fluctuations.