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Statue of Leonardo Fibonacci, Pisa, Italy.
The inscription reads, "A. Leonardo Fibonacci, Insigne
Matematico Piisano del Secolo XII."
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In Liber
Abacci, a problem is posed that gives rise to the sequence of numbers
1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, and so on to infinity, known
today as the Fibonacci sequence. The problem is this:
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How many
pairs of rabbits placed in an enclosed area can be produced in a single
year from one pair of rabbits if each pair gives birth to a new pair each
month starting with the second month?
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In arriving
at the solution, we find that each pair, including the first pair, needs a
month's time to mature, but once in production, begets a new pair each
month. The number of pairs is the same at the beginning of each of the
first two months, so the sequence is 1, 1. This first pair finally doubles
its number during the second month, so that there are two pairs at the
beginning of the third month. Of these, the older pair begets a third pair
the following month so that at the beginning of the fourth month, the
sequence expands 1, 1, 2, 3. Of these three, the two older pairs
reproduce, but not the youngest pair, so the number of rabbit pairs
expands to five. The next month, three pairs reproduce so the sequence
expands to 1, 1, 2, 3, 5, 8 and so forth. Figure 3-1 shows the Rabbit
Family Tree with the family growing with logarithmic acceleration.
Continue the sequence for a few years and the numbers become astronomical.
In 100 months, for instance, we would have to contend with
354,224,848,179,261,915,075 pairs of rabbits. The Fibonacci sequence
resulting from the rabbit problem has many interesting properties and
reflects an almost constant relationship
among its components.
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- The sum of any two
adjacent numbers in the sequence forms the next higher number in the
sequence, viz., 1 plus 1 equals 2, 1 plus 2 equals 3, 2 plus 3 equals
5, 3 plus 5 equals 8, and so on to infinity.
The Golden Ratio:-
- After the first several
numbers in the sequence, the ratio of any number to the next higher is
approximately .618 to 1 and to the next lower number approximately
1.618 to 1. The further along the sequence, the closer the ratio
approaches phi (denoted f) which is an irrational number,
.618034.... Between alternate numbers in the sequence, the ratio is
approximately .382, whose inverse is 2.618. Refer to Figure 3-2 for a
ratio table interlocking all Fibonacci numbers from 1 to 144.
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Fibonacci Arcs:-
The
calculation and interpretation of Fibonacci Arcs is similar to that of
Fibonacci Fan Lines. First, a trend line is drawn between two extreme
points. It draws three arcs, centered on the second extreme point, that
intersect the trend line drawn between the two extreme points at the
Fibonacci levels of 38.2%, 50.0%, and 61.8%.
The interpretation of Fibonacci Arcs involves looking for, or anticipating,
support and resistance as prices approach the arcs. A common technique is to
display both Fibonacci Arcs and Fibonacci Fan Lines and to anticipate
support/resistance at the points where the Fibonacci studies cross.
The points where the Arcs cross the price data will vary depending on
the scaling, because the Arcs are drawn so they always appear circular
relative to the computer screen.
Fibonacci Fans:-
Fibonacci
Fan Lines are displayed by first drawing a trend line between two extreme
points. It draws an invisible vertical line through the second extreme
point. This vertical line is then divided at the Fibonacci levels of 38.2%,
50.0%, and 61.8%. Finally, three trend lines are drawn from the first
extreme point so they pass through the invisible vertical line at the above
three levels. (This technique is similar to the method used to calculate
Speed Resistance Lines
Fibonacci Retracement:-
Fibonacci Retracements are displayed by first drawing a trend line between
two extreme points (i.e., a significant trough and peak). After selecting
Fibonacci Retracement from the Insert menu, a series of up to nine
horizontal lines will be drawn at the Fibonacci levels of 0.0%, 23.6%,
38.2%, 50.0%, 61.8%, 100%, 161.8%, 261.8%, and 423.6%.
After a significant move (either up or down), prices will often rebound
and retrace a significant portion (if not all) of the original move. As the
price retraces, support and resistance levels will often occur at or near
the Fibonacci Retracement levels.
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