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Date May Example question Marks available 2 Reference code EXM.1.AHL.TZ0.26
Level Additional Higher Level Paper Paper 1 Time zone Time zone 0
Command term Find Question number 26 Adapted from N/A

Question

Consider the matrices

A = (3254)(3254), B(1322)(1322).

Find BA.

[2]
a.

Calculate det (BA).

[2]
b.

 Find A(A–1B + 2A–1)A.

[3]
c.

Markscheme

BA((1322)(3254))=(181444)((1322)(3254))=(181444)             A2 

Note: Award A1 for one error, A0 for two or more errors.

[2 marks]

a.

det(BA) = (72 – 56) = 16            (M1)A1 

[2 marks]

b.

EITHER            

A(A–1B + 2A–1)A = BA + 2A            (M1)A1

=(241864)=(241864)        A1

OR

A–1 =12(4253)=12(4253)            (A1)

an attempt to evaluate            (M1)

A–1B + 2A–1 =12(016121)(4253)=12(016121)(4253)

A(A–1B + 2A–1)A = (3254)(464.57.5)(3254)(3254)(464.57.5)(3254)

=(3320)(3254)=(241864)=(3320)(3254)=(241864)              A1 

[3 marks]

c.

Examiners report

[N/A]
a.
[N/A]
b.
[N/A]
c.

Syllabus sections

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