Help with both 3 point formula and 4 points derivation

B.2. In class we derived the three-point formulae for f'(x). f(x,) and f'(x2). Consider a four-point case with (o. yo). (X1.34). (x2.)2) and (x3, #). Derive the four-point formulae for F(xa). P(x.). f'(x2) and f'(x3)