OCR H240/01 2018 June — Question 9 7 marks

Exam BoardOCR
ModuleH240/01 (Pure Mathematics)
Year2018
SessionJune
Marks7
PaperDownload PDF ↗
TopicSolving quadratics and applications
TypeQuadratic function range and roots analysis
DifficultyModerate -0.3 This is a straightforward quadratic function question requiring completion of the square (part i) and solving a simple equation (part ii). Both parts use standard techniques with no problem-solving insight needed, making it slightly easier than average for A-level.
Spec1.02e Complete the square: quadratic polynomials and turning points1.02v Inverse and composite functions: graphs and conditions for existence

9 The function f is defined for all real values of \(x\) as \(\mathrm { f } ( x ) = c + 8 x - x ^ { 2 }\), where \(c\) is a constant.
  1. Given that the range of f is \(\mathrm { f } ( x ) \leqslant 19\), find the value of \(c\).
  2. Given instead that \(\mathrm { ff } ( 2 ) = 8\), find the possible values of \(c\).

9 The function f is defined for all real values of $x$ as $\mathrm { f } ( x ) = c + 8 x - x ^ { 2 }$, where $c$ is a constant.\\
(i) Given that the range of f is $\mathrm { f } ( x ) \leqslant 19$, find the value of $c$.\\
(ii) Given instead that $\mathrm { ff } ( 2 ) = 8$, find the possible values of $c$.

\hfill \mbox{\textit{OCR H240/01 2018 Q9 [7]}}