Boll cashback forexger B cashbackforexbtcs East forex cashback by the upper, middle and lower three orbital lines composed of the upper and lower orbital lines are the trend of resistance (Up line) and support (Down line); the middle of that orbital line, that is, the middle rail, for the average of the Eastforexcashback forexcashbackcalculator is usually a 20-day simple moving average, the upper and lower orbital lines are calculated by: first calculate the standard deviation of the past 20 days closing price, and then multiply by 2 to get 2 times the Standard deviation of the upper rail line for the 20-day simple moving average plus 2 times the standard deviation, the lower rail line for the 20-day moving average minus 2 times the standard deviation in most cases, the exchange rate is always in the band consisting of the upper and lower rail line to run in the interval, and with the change in the exchange rate and automatically adjust the position of the rail from the width of the band can be seen in the rate of change, the wider the greater the change in price. Investors can also be based on the location of the exchange rate in the Bollinger Bands to assess the strength of its trend when the price line is located above the Bollinger Bands, the trend is strong, in the Bollinger Bands below, the trend is bearish Bollinger Bands of the two extreme upper and lower rails, said very strong and very weak Below are some simple principles for investors to choose the timing of buying and selling based on the Bollinger Bands (1) the exchange rate from the bottom up through the Down line can be seen as a buy signal; when the exchange rate crosses the lower limit of the support line, also for the buy signal (2) the exchange rate from the lower up through the middle line, it is possible to accelerate the upside, is the signal to buy additional positions. (3) the exchange rate fluctuations between the middle line and Up line running for the long market, you can hold more or add code, but when the exchange rate crosses the upper limit pressure line, is a sell signal (4) the exchange rate for a long time in the middle line and Up line after running, from up to down below the middle line for the sell signal (5) the exchange rate fluctuations between the middle line and Down line running for the short market, you can hold short or add throw