Find the approximated integral value of an equation 1/(x+1)^2 using Weddle's rule
a = 0 and b = 6
Interval n = 6Solution:Equation is `f(x)=(1)/(x+1)^2`
`a=0`
`b=6`
`Delta x =(b-a)/n=(6 - 0)/6=1`
The value of table for `x` and `f(x)`
| `x` | `f(x)` |
| `x_0=0` | `f(x_(0))=f(0)=1` |
| `x_1=1` | `f(x_(1))=f(1)=0.25` |
| `x_2=2` | `f(x_(2))=f(2)=0.1111` |
| `x_3=3` | `f(x_(3))=f(3)=0.0625` |
| `x_4=4` | `f(x_(4))=f(4)=0.04` |
| `x_5=5` | `f(x_(5))=f(5)=0.0278` |
| `x_6=6` | `f(x_(6))=f(6)=0.0204` |
Method-1:Using Weddle's Rule
`int f(x) dx=(3Delta x )/10 [(f(x_(0))+5f(x_(1))+f(x_(2))+6f(x_(3))+f(x_(4))+5f(x_(5))+f(x_(6)))+(f(x_(6))+5f(x_(7))+f(x_(8))+6f(x_(9))+f(x_(10))+5f(x_(11))+f(x_(12)))+...]`
`int f(x) dx=(3Delta x )/10 [(f(x_(0))+5f(x_(1))+f(x_(2))+6f(x_(3))+f(x_(4))+5f(x_(5))+f(x_(6)))]`
`f(x_(0))=1`
`5f(x_(1))=5*0.25=1.25`
`f(x_(2))=0.1111`
`6f(x_(3))=6*0.0625=0.375`
`f(x_(4))=0.04`
`5f(x_(5))=5*0.0278=0.1389`
`f(x_(6))=0.0204`
`int f(x) dx=(3xx1)/10*[(1+1.25+0.1111+0.375+0.040.1389+0.0204)]`
`=(3xx1)/10*(2.9354)`
`=0.8806`
Solution by Weddle's Rule is `0.8806`
Method-2:Using Weddle's Rule
`int f(x) dx=(3Delta x )/10 [(f(x_(0))+5f(x_(1))+f(x_(2))+6f(x_(3))+f(x_(4))+5f(x_(5))+f(x_(6)))+(f(x_(6))+5f(x_(7))+f(x_(8))+6f(x_(9))+f(x_(10))+5f(x_(11))+f(x_(12)))+...]`
`int f(x) dx=(3Delta x )/10 [(f(x_(0))+5f(x_(1))+f(x_(2))+6f(x_(3))+f(x_(4))+5f(x_(5))+f(x_(6)))]`
`=(3xx1)/10 [(1 + 5xx0.25 + 0.1111 + 6xx0.0625 + 0.04 + 5xx0.0278 + 0.0204)]`
`=(3xx1)/10 [2.9354]`
`=0.8806`
Solution by Weddle's Rule is `0.8806`
This material is intended as a summary. Use your textbook for detail explanation.
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