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The Definite Integral 
 The  Monte Carlo Method For Finding Area
     Activity 
     
    Pick four number from one to 100.  Instead of cutting the interval
    
    [0,100]  into five equal intervals, you can instead cut the interval
    at the four numbers that you chose and construct five rectangles as
    before.  We will approximate the area
of the curve under the curve  y = 
     
    from  1 to  100  to estimate the area.  
  
  
The Definite Integral 
 
     
      
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Definition 
 
Let  
 
          a 
=  x0,  x1,  ..., xn  = 
b  
 
 be a partition of [a,b]  and let
    
 
         
xi-1  <   ci  <
   xi  
 
then 
          
 
 
 
is called a   Reimann Sum, and the limit as the maximum
Dxi
 approaches  0  is called the   definite integral.  
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Note:  f(x) can be negative
 
Usually to compute a definite integral, we use left or right sums.
 
 
  
 
 
Special Cases 
 
 
 
 
 
Example:
 
 
 
 
  
 
 
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