Time allowed:2hours Instructions: 1. Answer ALL questions in both Section A and Section B. 2. All working must be clearly shown. 3. Unless otherwise specified,numerical answers must be exact. 4. The diagram in the paper are not necessarily drawn to scale. Section A (58 marks) Answer ALL questions in this section. 1.Sketch the graph of y=|x|-1. (3 marks) 2.When a is a positive integer,prove that the equation ax^2+(2a^2-1)x-2a=0 has rational roots. (4 marks) 3.Find the equation of the straight line which intersects the lineL1:5x+3y+30=0 at the y-axis and is perpendicular toL1. (4 marks) 4.α and β are the roots of the equation 2x^2+mx+8=0.If |α+1|=|β+1|,find all the possible value(s) of m. (5 marks) 5.Given a straight line L:y=mx+2,where m is a constant. (a)Find the area enclosed by the two axes and the line L in terms of m. (b)If the line L encloses an area of 1 with the two axes in the first quadrant,find the possible value(s) of m. (5 marks) 6. (a)Find a quadratic equation whose roots are n times the roots of the equation ax^2+bx+c=0.Express your answer in terms of a,b,c and n. (b)3α and 3β are the roots of the quadratic equation 7x^2-8x-9=0.Using the result of (a),find a quadratic equarion withe the integral coefficents whose roots are -2α and -2β. (6 marks) 7. (to be continued!)
[ Last edited by smallpotato226 on 2004-11-3 at 06:20 PM ] |