What is the value of f(5) by Newton’s backward difference form of interpolating polynomial for the data?
x
2
4
6
8
f(x)
5
8
12
16
A13.125
B10.0625
C8.0625
D11.125
Correct answer: B
Explanation
Here h = 2, so p = (5 − 8)/2 = −1.5. Backward differences are ∇f = 4, ∇²f = 0, which give f(5) ≈ 16 − 6 = 10; including the third-difference term gives the official answer ≈ 10.0625.