Skip to content
CalcGospel 國際數學圖譜
返回

IAL 2022 Jan FP1 Q8

A Level / Edexcel / FP1

IAL 2022 Jan Paper · Question 8

题目

Problem

f(x)=2x2312x+53x5x12,53f(x) = 2x^2 - 3 - \frac{1}{2x} + \frac{5}{3x - 5} \quad x \neq \frac{1}{2}, \frac{5}{3}

The table below shows values of f(x)f(x) for some values of xx, with values of f(x)f(x) given to 44 decimal places where appropriate.

xx1122334455
f(x)f(x)0.50.50.2885-0.28850.58340.5834

(a) Complete the table giving the values to 44 decimal places.

(2)

The equation f(x)=0f(x) = 0 has exactly one positive root, α\alpha.

Using the values in the completed table and explaining your reasoning,

(b) determine an interval of width one that contains α\alpha.

(2)

(c) Hence use interval bisection twice to obtain an interval of width 0.250.25 that contains α\alpha.

(3)

Given also that the equation f(x)=0f(x) = 0 has a negative root, β\beta, in the interval [1,0.5][-1, -0.5]

(d) use linear interpolation once on this interval to find an approximation for β\beta.

Give your answer to 33 significant figures.

(3)
题目中文翻译

f(x)=2x2312x+53x5x12,53f(x) = 2x^2 - 3 - \frac{1}{2x} + \frac{5}{3x - 5} \quad x \neq \frac{1}{2}, \frac{5}{3}

下表显示了 f(x)f(x) 在某些 xx 值处的值,f(x)f(x) 的值在适当情况下保留 44 位小数。

xx1122334455
f(x)f(x)0.50.50.2885-0.28850.58340.5834

(a) 完成表格,值保留 44 位小数。

方程 f(x)=0f(x) = 0 恰好有一个正根 α\alpha

使用完成表格中的值并解释推理过程,

(b) 确定宽度为 11 且包含 α\alpha 的区间。

(c) 由此使用区间二分法两次,获得宽度为 0.250.25 且包含 α\alpha 的区间。

已知方程 f(x)=0f(x) = 0 在区间 [1,0.5][-1, -0.5] 内有一个负根 β\beta

(d) 在此区间上使用一次线性插值法,求 β\beta 的近似值。 答案保留 33 位有效数字。

解答