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2. False Position method (regula falsi method) example ( Enter your problem )
  1. Algorithm & Example-1 `f(x)=x^3-x-1`
  2. Example-2 `f(x)=2x^3-2x-5`
  3. Example-3 `x=sqrt(12)`
  4. Example-4 `x=root(3)(48)`
  5. Example-5 `f(x)=x^3+2x^2+x-1`

3. Example-3 `x=sqrt(12)`





Find `sqrt(12)` using False Position method (regula falsi method)

Solution:
Let `x=sqrt(12)`

`:.x^2=12`

`:.x^2-12=0`

i.e. `f(x)=x^2-12`

Here
`x`01234
`f(x)`-12-11-8-34



`1^(st)` iteration :

Here `f(3) = -3 < 0` and `f(4) = 4 > 0`

`:.` Now, Root lies between `x_0 = 3` and `x_1 = 4`

`x_2 = x_0 - f(x_0) * (x_1 - x_0)/(f(x_1) - f(x_0))`

`x_2=3 - (-3) * (4 - 3)/(4 - (-3))`

`x_2=3.4286`

`f(x_2)=f(3.4286)=3.4286^2-12=-0.2449 < 0`


`2^(nd)` iteration :

Here `f(3.4286) = -0.2449 < 0` and `f(4) = 4 > 0`

`:.` Now, Root lies between `x_0 = 3.4286` and `x_1 = 4`

`x_3 = x_0 - f(x_0) * (x_1 - x_0)/(f(x_1) - f(x_0))`

`x_3=3.4286 - (-0.2449) * (4 - 3.4286)/(4 - (-0.2449))`

`x_3=3.4615`

`f(x_3)=f(3.4615)=3.4615^2-12=-0.0178 < 0`


`3^(rd)` iteration :

Here `f(3.4615) = -0.0178 < 0` and `f(4) = 4 > 0`

`:.` Now, Root lies between `x_0 = 3.4615` and `x_1 = 4`

`x_4 = x_0 - f(x_0) * (x_1 - x_0)/(f(x_1) - f(x_0))`

`x_4=3.4615 - (-0.0178) * (4 - 3.4615)/(4 - (-0.0178))`

`x_4=3.4639`

`f(x_4)=f(3.4639)=3.4639^2-12=-0.0013 < 0`


`4^(th)` iteration :

Here `f(3.4639) = -0.0013 < 0` and `f(4) = 4 > 0`

`:.` Now, Root lies between `x_0 = 3.4639` and `x_1 = 4`

`x_5 = x_0 - f(x_0) * (x_1 - x_0)/(f(x_1) - f(x_0))`

`x_5=3.4639 - (-0.0013) * (4 - 3.4639)/(4 - (-0.0013))`

`x_5=3.4641`

`f(x_5)=f(3.4641)=3.4641^2-12=0 < 0`


Approximate root of the equation `x^2-12=0` using False Position method is `3.4641` (After 4 iterations)

`n``x_0``f(x_0)``x_1``f(x_1)``x_2``f(x_2)`Update
13-3443.4286-0.2449`x_0 = x_2`
23.4286-0.2449443.4615-0.0178`x_0 = x_2`
33.4615-0.0178443.4639-0.0013`x_0 = x_2`
43.4639-0.0013443.46410`x_0 = x_2`







This material is intended as a summary. Use your textbook for detail explanation.
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