Date | May 2013 | Marks available | 3 | Reference code | 13M.2.hl.TZ2.1 |
Level | HL only | Paper | 2 | Time zone | TZ2 |
Command term | Find | Question number | 1 | Adapted from | N/A |
Question
A circle of radius 4 cm , centre O , is cut by a chord [AB] of length 6 cm.
Find AˆOB, expressing your answer in radians correct to four significant figures.
Determine the area of the shaded region.
Markscheme
EITHER
AˆOB=2arcsin(34) or equivalent (eg AˆOB=2arctan(3√7),AˆOB=2arccos(√74)) (M1)
OR
cosAˆOB=42+42−622×4×4 (=−18) (M1)
THEN
=1.696 (correct to 4sf) A1
[2 marks]
use of area of segment = area of sector – area of triangle (M1)
=12×42×1.696−12×42×sin1.696 (A1)
=5.63 (cm2) A1
[3 marks]
Examiners report
This was generally well done. In part (a), a number of candidates expressed the required angle either in degrees or in radians stated to an incorrect number of significant figures.
This was generally well done. In part (b), some candidates demonstrated a correct method to calculate the shaded area using an incorrect formula for the area of a sector.