Question

Derive or prove the three point backward difference approximation of the first derivative, aka D_h--f, of a function f(x), using either polynomial interpolant method (Newton's or Lagrange's) here is the first derivative approximation: f'(x) = (3* f(x) - 4*f(x-h)+ f(x-2h)) /2h , which is congruent to D_h--f

Answer 1

Doubt in this then comment below..i will explain you..

.

Please thumbs up for this solution..thanks..

.

here i use langrange interpolation