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IAL 2024 June FP3 Q5

A Level / Edexcel / FP3

IAL 2024 June Paper · Question 5

题目

Problem

4x2+4x+17(2x+p)2+q4x^2+4x+17\equiv(2x+p)^2+q

where pp and qq are integers.

(a) Determine the value of pp and the value of qq

Given that

8x+54x2+4x+1714x2+4x+17+Ax+B4x2+4x+17\frac{8x+5}{\sqrt{4x^2+4x+17}} \equiv \frac{1}{\sqrt{4x^2+4x+17}}+\frac{Ax+B}{\sqrt{4x^2+4x+17}}

where AA and BB are integers,

(b) write down the value of AA and the value of BB

(c) Hence use algebraic integration to show that

1/318x+54x2+4x+17dx=k+12lnk\int_{1/3}^1 \frac{8x+5}{\sqrt{4x^2+4x+17}}\,dx = k+\frac12\ln k

where kk is a rational number to be determined.

(8)
题目中文翻译 4x2+4x+17(2x+p)2+q4x^2+4x+17\equiv(2x+p)^2+q

其中 ppqq 为整数。

(a) 求 ppqq

已知

8x+54x2+4x+1714x2+4x+17+Ax+B4x2+4x+17\frac{8x+5}{\sqrt{4x^2+4x+17}} \equiv \frac{1}{\sqrt{4x^2+4x+17}}+\frac{Ax+B}{\sqrt{4x^2+4x+17}}

其中 AABB 为整数,

(b) 写出 AABB 的值

(c) 因此用代数积分证明

1/318x+54x2+4x+17dx=k+12lnk\int_{1/3}^1 \frac{8x+5}{\sqrt{4x^2+4x+17}}\,dx = k+\frac12\ln k

其中 kk 为待定有理数。

解答