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IAL 2020 Jan FP1 Q7

A Level / Edexcel / FP1

IAL 2020 Jan Paper · Question 7

题目

Problem

7. The equation 3x2+px5=03x^2 + px - 5 = 0, where pp is a constant, has roots α\alpha and β\beta.

(a) Determine the value of

(i) αβ\alpha\beta

(ii) (α+1β)(β+1α)\left(\alpha + \dfrac{1}{\beta}\right)\left(\beta + \dfrac{1}{\alpha}\right)

(3)

(b) Obtain an expression, in terms of pp, for

(i) α+β\alpha + \beta

(ii) (α+1β)+(β+1α)\left(\alpha + \dfrac{1}{\beta}\right) + \left(\beta + \dfrac{1}{\alpha}\right)

(3)

Given that

(α+1β)2+(β+1α)2=2(α+1β)(β+1α)\left(\alpha + \dfrac{1}{\beta}\right)^2 + \left(\beta + \dfrac{1}{\alpha}\right)^2 = 2\left(\alpha + \dfrac{1}{\beta}\right)\left(\beta + \dfrac{1}{\alpha}\right)

(c) determine the value of pp.

(1)

(d) Using the value of pp found in part (c), obtain a quadratic equation, with integer coefficients, that has roots (α+1β)\left(\alpha + \dfrac{1}{\beta}\right) and (β+1α)\left(\beta + \dfrac{1}{\alpha}\right)

(2)
题目中文翻译
  1. 方程 3x2+px5=03x^2 + px - 5 = 0,其中 pp 是常数,有根 α\alphaβ\beta

(a) 求下列各式的值

(i) αβ\alpha\beta

(ii) (α+1β)(β+1α)\left(\alpha + \dfrac{1}{\beta}\right)\left(\beta + \dfrac{1}{\alpha}\right)

(b) 用 pp 表示下列各式

(i) α+β\alpha + \beta

(ii) (α+1β)+(β+1α)\left(\alpha + \dfrac{1}{\beta}\right) + \left(\beta + \dfrac{1}{\alpha}\right)

已知

(α+1β)2+(β+1α)2=2(α+1β)(β+1α)\left(\alpha + \dfrac{1}{\beta}\right)^2 + \left(\beta + \dfrac{1}{\alpha}\right)^2 = 2\left(\alpha + \dfrac{1}{\beta}\right)\left(\beta + \dfrac{1}{\alpha}\right)

(c) 求 pp 的值。

(d) 利用 (c) 中求得的 pp 值,求一个整系数二次方程,使其根为 (α+1β)\left(\alpha + \dfrac{1}{\beta}\right)(β+1α)\left(\beta + \dfrac{1}{\alpha}\right)

解答