2022 ZHSS AMath Prelims P2 Ans

[Turn over ZHONGHUA SECONDARY SCHOOL PRELIMINARY EXAMINATION 2022 SECONDARY 4 EXPRESS/ 5 NORMAL (ACADEMIC) Candidate’s Name Class Register Number MARKING SCHEME ADDITIONAL MATHEMATICS 4049/02 PAPER 2 13 September 2022 2 hour 15 minutes Candidates answer on the Question Paper READ THESE INSTRUCTIONS FIRST Write your name, class and register number on all the work you hand in. Write in dark blue or black pen on both sides of the paper. You may use an HB pencil for any diagrams or graphs. Do not use paper clips, glue or correction fluid. Answer all questions. Give non-exact numerical answers correct to 3 significant figures, or 1 decimal place in the case of angles in degrees, unless a different level of accuracy is specified in the question. The use of an approved scientific calculator is expected, where appropriate. You are reminded of the need for clear presentation in your answers. The number of marks is given in brackets [ ] at the end of each question or part question. The total number of marks for this paper is 90. ___________________________________________________________________ This question paper consists of 21 printed pages (including this cover page) For Examiner’s Use 90

2 Mathematical Formulae 1. ALGEBRA Quadratic Equation For the equation 02 =++ cbxax a acbbx 2 42 −−= Binomial expansion nrrnnnnn bbar nbanbanaba ++     ++     +     +=+ −−− 221 21)( , where n is a positive integer and ! )1()1( )!(! ! r rnnn rnr n r n +−−=−=       2. TRIGONOMETRY Identities 1cossin 22 =+ AA AA 22 tan1sec += 22cosec 1 cotAA=+ BABABA sincoscossin)sin( = BABABA sinsincoscos)cos( = BA BABA tantan1 tantan)tan(  = AAA cossin22sin = AAAAA 2222 sin211cos2sincos2cos −=−=−= A AA 2tan1 tan22tan −= Formulae for ABC C c B b A a sinsinsin == Abccba cos2222 −+= Abcsin2 1=

3 1 (a) By using suitable substitution or otherwise, solve the equation ( )e 3 e 5ex x x− −= , giving your answer correct to 2 decimal places. [4] ( )( ) 2 2 2 2 3 15 35 5 3 0 Let 5 3 0 1 1 4 5 3 10 1 61 10 1 61 (rej. negative)10 1 61ln 10 0.384156 0.38 (2 d.p) x x xx xx x x ee ee ee ue uu u e x −= −= + − = = + − = −  − −= −= −+= −+=  =− =− B1- Quadratic equation M1- Quadratic Formula M1 A1

4 (b) Solve 75xx+ = − . [3] ( ) ( )( ) 2 2 2 7 10 25 11 18 0 9 2 0 9 or 2 (rejected) 9 75 75 x x x x x x x xx x xx x x + = − + − + = − − = == + = − −  = = + 2 Given that tan p = and that  is acute, find in terms of p, (a) ( )sin − [1] ( ) 2 sin sin 1 p p − =− + =− (b) tan 2   − [1] 1tan 2 p   −= M1- Square both sides M1- Solving quadratic equation A1 B1 B1- o.