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Date November 2009 Marks available 5 Reference code 09N.1.hl.TZ0.1
Level HL only Paper 1 Time zone TZ0
Command term Find Question number 1 Adapted from N/A

Question

When \(3{x^5} - ax + b\) is divided by x −1 and x +1 the remainders are equal. Given that a , \(b \in \mathbb{R}\) , find

(a)     the value of a ;

(b)     the set of values of b .

Markscheme

(a)     \(f(1) = 3 - a + b\)     (A1)

\(f( - 1) = - 3 + a + b\)     (A1)

\(3 - a + b = - 3 + a + b\)     M1

\(2a = 6\)

\(a = 3\)     A1     N4

 

(b)     b is any real number     A1

[5 marks]

Examiners report

Many candidates answered part (a) successfully. For part (b), some candidates did not consider that the entire set of real numbers was asked for.

Syllabus sections

Topic 2 - Core: Functions and equations » 2.5 » The factor and remainder theorems.

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