Home > Numerical methods > Numerical Differentiation > Two point Forward difference, Backward difference, Central difference formula numerical differentiation example

1. Two point Forward difference, Backward difference, Central difference formula numerical differentiation example ( Enter your problem )
  1. Formula & Example-1 (table data)
  2. Example-2 (table data)
  3. Example-3 (`f(x)=cosx`)
  4. Example-4 (`f(x)=2x^3+x^2-4`)
  5. Example-5 (`f(x)=xlnx`)
  6. Example-6 (`f(x)=sinx`)

4. Example-4 (`f(x)=2x^3+x^2-4`)





`f(x)=2x^3+x^2-4` and `h = 0.5`, estimate `f^'(2.5) and f^('')(2.5)`
using Two point Forward difference, Backward difference, Central difference formula numerical differentiation
Also find exact value of f', f'' and error for each estimation


Solution:
Equation is `f(x) = 2x^3+x^2-4`.

`:. f^'(x) = 6x^2+2x`

`:. f^('')(x) = 12x+2`

The value of table for `x` and `y`

x22.53
y1633.559

Two-point FDF (Forward difference formula)
`f^'(x)=(f(x+h)-f(x))/h`

`f^'(2.5)=(f(2.5+0.5)-f(2.5))/0.5`

`f^'(2.5)=(f(3)-f(2.5))/0.5`

`f^'(2.5)=(59-33.5)/0.5`

`f^'(2.5)=51`

Absolute Error:`|"exact value of " f^'(2.5)-(51)|=|42.5 -51|=8.5`



Two-point BDF (Backward difference formula)
`f^'(x)=(f(x)-f(x-h))/h`

`f^'(2.5)=(f(2.5)-f(2.5-0.5))/0.5`

`f^'(2.5)=(f(2.5)-f(2))/0.5`

`f^'(2.5)=(33.5-16)/0.5`

`f^'(2.5)=35`

Absolute Error:`|"exact value of " f^'(2.5)-(35)|=|42.5 -35|=7.5`



Two-point CDF (Central difference formula)
`f^'(x)=(f(x+h)-f(x-h))/(2h)`

`f^'(2.5)=(f(2.5+0.5)-f(2.5-0.5))/(2*0.5)`

`f^'(2.5)=(f(3)-f(2))/1`

`f^'(2.5)=(59-16)/1`

`f^'(2.5)=43`

Absolute Error:`|"exact value of " f^'(2.5)-(43)|=|42.5 -43|=0.5`




This material is intended as a summary. Use your textbook for detail explanation.
Any bug, improvement, feedback then Submit Here





Share this solution or page with your friends.
 
 
Copyright © 2026. All rights reserved. Terms, Privacy
 
 

.