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 (1.7,9.1),{(-1.7, 9.1),} (1.6,3.8){(1.6, 3.8)} and (3.2,7.6),{(3.2, 7.6),} 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