Excel mmult() function the first time
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 Example 1:
           type a row         1, 2, 3    
           type a column
           1
           2
           3

   =mmult(myRow,myClumn)    Ctrl-Shit-Enter
     1*1 + 2*2 + 3*4 = 14

 Example 2: two column 
            1    2
            2    1
            3    5

     =mmult(tranpose(Column_01),column_2)

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Future value of an annuity
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 If the first cash flow happens at the end of the first period, 
     we have the following formula. 
                   c
     fv_annuity = ---*[ (1+R)^n -1 ]
                   R

     c: a constant cash flow 
     R: period rate
     n: the number of periods

  What is the future value if we will receive $15 at the end of 
     each year for the next 20 years? Assume that the annual discount
     rate is 3%. 
     > 15/0.03*((1+0.03)^20-1) 
       [1] 403.0556

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one column (n *1) times a row (1 * m ) will be a matrix (n * m)
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Assume that we have the following column ( 5 by 1)
  1
  2
  3
  3
  5

Our row is 1 by 3
  1  2  5


 Our final result will be 5 by 3

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One row times the transpose of itself
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 Assume that we have a set of values and we want to estimate the sum of their squared value. 

  Here is a example. We have 1, 3, 5 and 10. We want to estimate 1^2 + 3^2 + 5^2 and 10^2=?

    we generate a row and assume that they are in A1 to D1. 
       1 3  5 10

     =mmult(A1:D1,transpose(A1:D1))

   After hit Ctrl-Shift-Enter, we will see 135 appear in the cell. 

   The following would appear in the formula bar. 

      {=MMULT(A1:D1,TRANSPOSE(A1:D1))}

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One row times the transpose of another row
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If we have the same number of values for both row and column then we 

         could use the following formula 


   =mmult(myRow, transpose(myColumn))

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