Answer:
Negative Directional Movement (-DM) is calculated as:
−DM=
EMATR
EMADOWN
where:
EMADOWN = Exponential moving average of downward
price movements
EMATR = Exponential moving average of the true
range of prices
Explanation:
The DMI is actually two different standard indicators, one negative and one positive, that are plotted as lines on the same chart. A third line, the average directional index, or ADX, is nondirectional but shows movement strength.
There is a different formula used for each of the three indicators. The DMI is built on a ratio of exponential moving averages, or EMAs, of the upward price movements (U), downward price movements (D) and the true range of the prices (TR). These are often expressed in an equation as EMAUP, EMADOWN and EMATR.
The computations for the various EMAs are complex and numerous. Once they are found, however, they can be used to compute the directional movement, or DM, for whatever time interval is selected. The standard interval is 14 periods. The returned value of DM can be positive (+DM), negative (-DM), or zero.
Hope it helppss :))