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Pascal’s Triangle and its
applications and properties
     Jordan Leong 3O3 10
History
• It is named after a French Mathematician
  Blaise Pascal
• However, he did not invent it as it was already
  discovered by the Chinese in the 13th century
  and the Indians also discovered some of it
  much earlier.
• There were many variations but they
  contained the same idea
History
• The Chinese’s version of the Pascal’s triangle
  was found in Chu Shi-Chieh's book "Ssu Yuan
  Yü Chien" (Precious Mirror of the Four
  Elements), written in AD 1303 which is more
  than 700 years ago and also more than 300
  years before Pascal discovered it. The book
  also mentioned that the triangle was known
  about more than two centuries before that.
History
• This is how
  the Chinese’s
  “Pascal’s
  triangle” looks
  like
What is Pascal’s Triangle
            1
          1 1
         1 2 1
        1 3 3 1
       1 4 6 4 1
     1 5 10 10 5 1
    1 6 15 20 15 6 1
Pascal’s Triangle
 Simply put, the Pascal’s Triangle is made up of
the powers of 11, starting 11 to the power of 0
as can be seen from the previous slide
Interesting Properties
In this case, 3 is the    1
sum of the
two numbers           1 1
above it, namely 1
and 2
                     1 2 1
                    1 3 3 1 6 is the sum of 5 and 1
                   1 4 6 4 1
                 1 5 10 10 5 1
                1 6 15 20 15 6 1
Interesting Properties
• If a line is drawn vertically down through the
  middle of the Pascal’s Triangle, it is a mirror
  image, excluding the center line.
Interesting Properties
When diagonals               1
                       1     2
Across the triangle
are drawn out the     1 1    5
following sums are   1 2 1
obtained. They                13
                    1 3 3 1
follow the formula
of X=(3n-1) with n 1 4 6 4 1
being the number 1 5 10 10 5 1
before X
             1 6 15 20 15 6 1
Interesting Properties
    1
    1    1
    1    2     1
    1    3     3    1
    1    4     6    4    1
    1    5     10   10   5    1
    1    6     15   20   15   6    1
    1    7     21   35   35   21   7    1
    1    8     28   56   70   56   28   8     1

In this case, when the triangle is left-justified,
the sum of the same coloured diagonals
lined out form the Fibonacci sequence
Interesting Properties
• If all the even numbers are coloured white
  and all the odd numbers are coloured black, a
  pattern similar to the Sierpinski gasket would
  appear.
Interesting Properties
          1    In this diagonal,
         1 1   counting numbers
        1 2 1  can be observed
       1 3 3 1
      1 4 6 4 1
    1 5 10 10 5 1
   1 6 15 20 15 6 1
Interesting Properties
       1
                   The next diagonal
      1 1          forms the
     1 2 1         sequence of
                   triangular numbers.
    1 3 3 1        Triangular numbers is
   1 4 6 4 1       a sequence
 1 5 10 10 5 1     generated from a
                   pattern of dots
1 6 15 20 15 6 1   which form a triangle
Interesting Properties

       1           This diagonal contains
      1 1          tetrahedral numbers.
                   It is made up of numbers
     1 2 1
                   that form the number of
    1 3 3 1        dots in a tetrahedral
   1 4 6 4 1       according to layers
 1 5 10 10 5 1
1 6 15 20 15 6 1
Application – Binomial Expansion
• (a+b)2 = 1a2 + 2ab + 1b2

• The observed pattern is that the coefficient of
  the expanded values follow the Pascal’s
  triangle according to the power. In this case,
  the coefficient of the expanded follow that of
  112 (121)
Application - Probability
• Pascal's Triangle can show you how many
  ways heads and tails can combine. This can
  then show you the probability of any
  combination.
• In the following slide, H represents Heads and
  T represents Tails
Application - Probability
• For example, if a coin is tossed 4 times, the
  possibilities of combinations are
• HHHH
• HHHT, HHTH, HTHH, THHH
• HHTT, HTHT, HTTH, THHT, THTH, TTHH
• HTTT, THTT, TTHT, TTTH
• TTTT
• Thus, the observed pattern is 1, 4, 6, 4 1
Application - Probability
• If one is looking for the total number of
  possibilities, he just has to add the numbers
  together.
Application - Combination
• Pascal’s triangle can also be used to find
  combinations:
• If there are 5 marbles in a bag, 1 red, 1blue, 1
  green, 1 yellow and 1 black. How many different
  combinations can I make if I take out 2 marbles
• The answer can be found in the 2nd place of row
  5, which is 10. This is taking note that the rows
  start with row 0 and the position in each row also
  starts with 0.
Purpose
• I chose this topic because while we were
  choosing a topic for Project’s Day
  Competition, I researched up on Pascal’s
  triangle and found that it has many interesting
  properties. It is not just a sequence and has
  many applications and can be said to be
  mathematical tool. Therefore, I decided to
  explore this now and learned many interesting
  new facts and uses of the Pascal’s triangle.
Sources
• http://en.wikipedia.org/wiki/Pascal's_triangle
• Zeuscat.com
• http://www.mathsisfun.com/algebra/triangul
  ar-numbers.html
• http://www.mathsisfun.com/pascals-
  triangle.html
• http://bjornsmaths.blogspot.sg/2005/11/pasc
  als-triangle-in-chinese.html
Thank You