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Date November 2016 Marks available 5 Reference code 16N.2.AHL.TZ0.H_2
Level Additional Higher Level Paper Paper 2 Time zone Time zone 0
Command term Find Question number H_2 Adapted from N/A

Question

Find the acute angle between the planes with equations x + y + z = 3 and 2 x z = 2 .

Markscheme

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

n 1 = ( 1 1 1 ) and n 2 = ( 2 0 1 )      (A1)(A1)

EITHER

θ = arccos ( n 1 n 2 | n 1 | | n 2 | ) ( cos θ = n 1 n 2 | n 1 | | n 2 | )    (M1)

= arccos ( 2 + 0 1 3 5 ) ( cos θ = 2 + 0 1 3 5 )    (A1)

= arccos ( 1 15 ) ( cos θ = 1 15 )

OR

θ = arcsin ( | n 1 × n 2 | | n 1 | | n 2 | ) ( sin θ = | n 1 × n 2 | | n 1 | | n 2 | )    (M1)

= arcsin ( 14 3 5 ) ( sin θ = 14 3 5 )    (A1)

= arcsin ( 14 15 ) ( sin θ = 14 15 )

 

THEN

= 75.0  (or 1.31)    A1

[5 marks]

Examiners report

[N/A]

Syllabus sections

Topic 3— Geometry and trigonometry » AHL 3.18—Intersections of lines & planes
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Topic 3— Geometry and trigonometry

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