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Date May Example question Marks available 4 Reference code EXM.1.AHL.TZ0.3
Level Additional Higher Level Paper Paper 1 Time zone Time zone 0
Command term Find Question number 3 Adapted from N/A

Question

A and B  are 2 × 2 matrices, where  A = [ 5 2 2 0 ] and  B A = [ 11 2 44 8 ] . Find  B

Markscheme

* This question is from an exam for a previous syllabus, and may contain minor differences in marking or structure.

B = ( B A ) A 1      (M1)

= 1 4 ( 11 2 44 8 ) ( 0 2 2 5 )      (M1)

= 1 4 ( 4 12 16 48 )       (A1)

= ( 1 3 4 12 )       (A1)

OR

( a b c d ) ( 5 2 2 0 ) = ( 11 2 44 8 )      (M1)

5 a + 2 b = 11 2 a = 2 }

a = 1 ,   b = 3      (A1)

5 c + 2 d = 44 2 c   = 8 }

c = 4 ,   d = 12      (A1)

B = ( 1 3 4 12 )      (A1) (C4)

Note: Correct solution with inversion (ie AB instead of BA) earns FT marks, (maximum [3 marks]).

[4 marks]

Examiners report

[N/A]

Syllabus sections

Topic 1—Number and algebra » AHL 1.14—Introduction to matrices
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Topic 1—Number and algebra

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