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IAL 2019 May FP1 Q6

A Level / Edexcel / FP1

IAL 2019 May Paper · Question 6

Question

[!problem]

The quadratic equation

2x2+x+4=02x^2 + x + 4 = 0

has roots α\alpha and β\beta.

Without solving the quadratic equation,

(a) write down the value of (α+β)(\alpha + \beta) and the value of αβ\alpha\beta.

(b) find the value of

(i) α2+β2\alpha^2 + \beta^2

(ii) α4+β4\alpha^4 + \beta^4

(c) find a quadratic equation that has roots

1α2 and 1β2\frac{1}{\alpha^2} \text{ and } \frac{1}{\beta^2}

giving your answer in the form px2+qx+r=0px^2 + qx + r = 0, where pp, qq and rr are integers.

(4)

中文翻译

二次方程

2x2+x+4=02x^2 + x + 4 = 0

有根 α\alphaβ\beta

不解二次方程,

(a) 写出 (α+β)(\alpha + \beta) 的值和 αβ\alpha\beta 的值。

(b) 求下列各式的值

(i) α2+β2\alpha^2 + \beta^2

(ii) α4+β4\alpha^4 + \beta^4

(c) 求一个二次方程,使其根为

1α2 和 1β2\frac{1}{\alpha^2} \text{ 和 } \frac{1}{\beta^2}

将答案写成 px2+qx+r=0px^2 + qx + r = 0 的形式,其中 ppqqrr 是整数。

(4)