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IAL 2021 Oct FP1 Q2

A Level / Edexcel / FP1

IAL 2021 Oct Paper · Question 2

题目

Problem

2. f(x)=7x12x53xx>0f(x) = 7x - \dfrac{1}{2}x - \dfrac{5}{3x} \quad x > 0

(a) Show that the equation f(x)=0f(x) = 0 has a root, α\alpha, in the interval [2.8,2.9][2.8, 2.9]

(2)

(b) (i) Find f(x)f'(x).

(ii) Hence, using x0=2.8x_0 = 2.8 as a first approximation to α\alpha, apply the Newton-Raphson procedure once to f(x)f(x) to calculate a second approximation to α\alpha, giving your answer to 3 decimal places.

(4)

(c) Use linear interpolation once on the interval [2.8,2.9][2.8, 2.9] to find another approximation to α\alpha. Give your answer to 3 decimal places.

(3)
题目中文翻译
  1. f(x)=7x12x53xx>0f(x) = 7x - \dfrac{1}{2}x - \dfrac{5}{3x} \quad x > 0

(a) 证明方程 f(x)=0f(x) = 0 在区间 [2.8,2.9][2.8, 2.9] 内有一个根 α\alpha

(b) (i) 求 f(x)f'(x)

(ii) 取 x0=2.8x_0 = 2.8 作为 α\alpha 的第一个近似值,对 f(x)f(x) 应用一次 Newton-Raphson 法,计算 α\alpha 的第二个近似值,答案保留 3 位小数。

(c) 在区间 [2.8,2.9][2.8, 2.9] 上使用一次线性插值,求 α\alpha 的另一个近似值。答案保留 3 位小数。

解答