Numerical Integration Example using Right Endpoint for Riemann Sum

 

Estimate the area under the curve,  y(x)  =  x2  , from   a  =  1   to   b  =  3   .

 

Note for this increasing function, the right endpoint Riemann Sum

overestimates the area.

 

 

                         rightendexamplea.jpg

 

 

Note:  The approximate area  =  ( y1  +  y2  +  y3  +  y4 ) Δx

 

Here   b  =  3,    a  =  1,    n  =  4         so  Δx  =  (3 – 1)/4  =  0.5

 

   Here      xi  =  a  +  i Δx

 

x1 = 1.5,       x2 = 2.0,    x3 = 2.5,             x3 = 3.0

 

y1  =  2.25,  y2  =  4,     y3  =  6.25, and   y4=  9

 

 

                            Approximate area  =    (  2.25  +  4  +  6.5 + 9 ) 0.5   =   10.875

 

Click here to use the Riemann Sum to calculate the exact area.

 


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