OCR MEI FP1 2008 January — Question 3 7 marks

Exam BoardOCR MEI
ModuleFP1 (Further Pure Mathematics 1)
Year2008
SessionJanuary
Marks7
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicRoots of polynomials
TypeFactor theorem and finding roots
DifficultyModerate -0.8 This is a straightforward application of the factor theorem with routine algebraic manipulation. Substituting z=3 is trivial verification, factoring out (z-3) is standard, and solving the resulting quadratic requires only the quadratic formula. The Argand diagram is basic plotting. Despite being Further Maths, this is a textbook exercise requiring only recall and standard techniques with no problem-solving insight.
Spec4.02j Cubic/quartic equations: conjugate pairs and factor theorem4.02k Argand diagrams: geometric interpretation

3
  1. Show that \(z = 3\) is a root of the cubic equation \(z ^ { 3 } + z ^ { 2 } - 7 z - 15 = 0\) and find the other roots.
  2. Show the roots on an Argand diagram.

3 (i) Show that $z = 3$ is a root of the cubic equation $z ^ { 3 } + z ^ { 2 } - 7 z - 15 = 0$ and find the other roots.\\
(ii) Show the roots on an Argand diagram.

\hfill \mbox{\textit{OCR MEI FP1 2008 Q3 [7]}}