Prime DSE Series - Mathematics Mock Exam Papers (Extended Part) Module 1 Set 3

HKDSE-MATH-EP(M1)(Set 3) − 16 16 © United Prime Educational Publishing (HK) Ltd. Answers written in the margins will not be marked. Answers written in the margins will not be marked. Answers written in the margins will not be marked. 11. A doctor studies the amount of antibodies ( A units) in the blood of a person after vaccination. It is found that the amount of the antibodies in the blood can be modelled by 4 2 4 28 17 28 4( 1) t t A t + + = + , where t ( t ≥ 0) is the number of days elapsed since the vaccination. (a) A person after vaccination is regarded as well protected when the amount of antibodies in the blood is at least 8 units. Find the range of values of t such that a person is well protected . (2 marks) (b) Find the greatest value and the least value of A . (6 marks) (c) Find the greatest value of the rate of change of A , where 0 < t < 1. (4 marks) Sample © United Prime Educational Publishing (HK) Limited All rights reserved; no part of this publication may be reproduced, photocopied, recorded or otherwise, without the prior written permission of the Publisher.