Question 0111b

Equations and Inequalities
2011 Paper 1 Question 2 Variant

Question

It is given that f(x)=ax2+bx+c,{f(x)=ax^2+bx+c,} where a,b{a,b} and c{c} are constants.
(i)
Given that the curve with equation y=f(x){y=f(x)} passes through the points with coordinates (0.9,2.9),{(-0.9, -2.9),} (2.2,3.5){(2.2, 3.5)} and (3.1,6.5),{(3.1, 6.5),} find the values of a,b{a,b} and c.{c.} Give your answers correct to 3 decimal places.
[3]
(ii)
Find the set of values of x{x} for which f(x){f(x)} is a decreasing function.
[2]

Answer