User interface language: English | Español

Date May 2017 Marks available 2 Reference code 17M.2.AHL.TZ2.H_4
Level Additional Higher Level Paper Paper 2 Time zone Time zone 2
Command term Find Question number H_4 Adapted from N/A

Question

Find the set of values of k that satisfy the inequality k 2 k 12 < 0 .

[2]
a.

The triangle ABC is shown in the following diagram. Given that cos B < 1 4 , find the range of possible values for AB.

M17/5/MATHL/HP2/ENG/TZ2/04.b

[4]
b.

Markscheme

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

k 2 k 12 < 0

( k 4 ) ( k + 3 ) < 0      (M1)

3 < k < 4      A1

[2 marks]

a.

cos B = 2 2 + c 2 4 2 4 c   ( or  16 = 2 2 + c 2 4 c cos B )      M1

c 2 12 4 c < 1 4      A1

c 2 c 12 < 0

from result in (a)

0 < AB < 4 or 3 < AB < 4      (A1)

but AB must be at least 2

2 < AB < 4      A1

 

Note:     Allow AB for either of the final two A marks.

 

[4 marks]

b.

Examiners report

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

Syllabus sections

Topic 3—Geometry and trigonometry » SL 3.2—2d and 3d trig
Show 99 related questions
Topic 3—Geometry and trigonometry » AHL 3.8—Unit circle, Pythag identity, solving trig equations graphically
Topic 3—Geometry and trigonometry

View options