(Ex 4.1.24, p.183) Derive an O(h4) five-point formula to approximate f'(x0) that uses f(xo - h), f(xo), f(xo+h), f(xo+2h) and f(x0+3h). (Hint: Consider the expression Af(xo - h) + Bf(xo+h)+Cf(xo+ 2h) + Df(xo + 3h). Expand in fourth Taylor polynomials and choose A, B, C and D appropriately.) 24. a. Analyze the round-off errors, as in Example 4, for the formula f(xo+h) f(xo) h f'(xo) = ƒ" (§o). h 2