2021 NTSS Prelim 4E AM P1 MS v20210804a

This document consists of 17 printed pages. Setter: Mr Alan Cheng NEW TOWN SECONDARY SCHOOL Preliminary Examination Secondary 4 Express NAME Mark Scheme CLASS INDEX NUMBER Additional Mathematics Paper 1 4049/01 28 July 2021 10:35 – 12:50 2 hours 15 min READ THESE INSTRUCTIONS FIRST Write your name, register number and class in the spaces provided above and on all the work you hand in. Write in dark blue or black pen. You may use an HB pencil for any diagrams or graphs. Do not use paper clips, glue or correction fluid. Answer all the 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. For Examiner’s Use

2 Mathematical Formulae 1. ALGEBRA Quadratic Equation For the equation 02 =++ cbxax , 2( 4 ) 2 b b acx a −  −= . Binomial Expansion nrrnnnnn bbar nbanbanaba ++     ++     +     +=+ −−− 221 21)( , where n is a positive integer and ( ) ! ( 1) ( 1) ! ! ! n n n n n r r r n r r  − − +== − 2. TRIGONOMETRY Identities sin2 A + cos2 A = 1 sec2 A = 1 + tan2 A cosec2 A = 1 + cot2 A BABABA sincoscossin)sin( = BABABA sinsincoscos)cos( = BA BABA tantan1 tantan)tan(  = AAA cossin22sin = AAAAA 2222 sin211cos2sincos2cos −=−=−= A AA 2tan1 tan22tan −= Formulae for ABC A a sin = B b sin = C c sin a2 = b2 + c2 − 2bc cos A  = 2 1 bc sin A

3 1 The curve 2 4 xy xba− = + , where a and b are constants, intersects the y-axis at A and the x-axis at B and C. The coordinates of B are ( )2,0− . Given that the gradient of AB is 3− , find the value of a and of b. [5] Sub ( )2,0B − , ( ) 2 2 0 24 ba − − =− + [M1] 3b= [A1] Sub 0,x= 3b= , y ba−= 3ya=− --- (1) [M1] ( )0, 3Aa − Gradient of AB ( )03 320 a−−= =−−− [M1] 3 32 a =−− 2a= [A1]

4 2 The equation of a curve is 3 cos 22y c x=− where c is a constant. The curve passes through the point 1,64   . (a) Find the value of c. [2] Sub 1,64   13 cos 24 2 6c =−  [M1] 1 3 1 4 2 2c =−  1c= [A1] (b) Using the value of c found in part (a), sketch the graph of 3 cos 22y c x=− for 02 x  . [B1 – 2 complete cycles] [B1 – start and end at -0.5] [B1 – fully correct curve with correct Max value @ 2.5