SPS SPS FM 2024 November — Question 14

Exam BoardSPS
ModuleSPS FM (SPS FM)
Year2024
SessionNovember
TopicDifferentiation Applications
TypeFind stationary points

14 November 2024 Instructions
  • Answer all the questions.
  • Use black or blue ink. Pencil may be used for graphs and diagrams only.
  • There are blank pages at the end of the paper for additional working. You must clearly indicate when you have moved onto additional pages on the question itself. Make sure to include the question number.
  • You are permitted to use a scientific or graphical calculator in this paper.
  • Where appropriate, your answer should be supported with working. Marks might be given for using a correct method, even if your answer is wrong.
  • Give non-exact numerical answers correct to 3 significant figures unless a different degree of accuracy is specified in the question.
  • The acceleration due to gravity is denoted by \(g \mathrm {~ms} ^ { - 2 }\). When a numerical value is needed use \(g = 9.8\) unless a different value is specified in the question.
Information
  • The total mark for this paper is \(\mathbf { 6 1 }\) marks.
  • The marks for each question are shown in brackets.
  • You are reminded of the need for clear presentation in your answers.
  • You have \(\mathbf { 6 0 }\) minutes for this paper.
\section*{Arithmetic series} \(S _ { n } = \frac { 1 } { 2 } n ( a + l ) = \frac { 1 } { 2 } n \{ 2 a + ( n - 1 ) d \}\) \section*{Geometric series} \(S _ { n } = \frac { a \left( 1 - r ^ { n } \right) } { 1 - r }\)
\(S _ { \infty } = \frac { a } { 1 - r }\) for \(| r | < 1\) \section*{Binomial series} \(( a + b ) ^ { n } = a ^ { n } + { } ^ { n } \mathrm { C } _ { 1 } a ^ { n - 1 } b + { } ^ { n } \mathrm { C } _ { 2 } a ^ { n - 2 } b ^ { 2 } + \ldots + { } ^ { n } \mathrm { C } _ { r } a ^ { n - r } b ^ { r } + \ldots + b ^ { n } \quad ( n \in \mathbb { N } )\),
where \({ } ^ { n } \mathrm { C } _ { r } = { } _ { n } \mathrm { C } _ { r } = \binom { n } { r } = \frac { n ! } { r ! ( n - r ) ! }\)
\(( 1 + x ) ^ { n } = 1 + n x + \frac { n ( n - 1 ) } { 2 ! } x ^ { 2 } + \ldots + \frac { n ( n - 1 ) \ldots ( n - r + 1 ) } { r ! } x ^ { r } + \ldots \quad ( | x | < 1 , n \in \mathbb { R } )\) \section*{Series} \(\sum _ { r = 1 } ^ { n } r ^ { 2 } = \frac { 1 } { 6 } n ( n + 1 ) ( 2 n + 1 ) , \sum _ { r = 1 } ^ { n } r ^ { 3 } = \frac { 1 } { 4 } n ^ { 2 } ( n + 1 ) ^ { 2 }\) \section*{Maclaurin series} \(\mathrm { f } ( x ) = \mathrm { f } ( 0 ) + \mathrm { f } ^ { \prime } ( 0 ) x + \frac { \mathrm { f } ^ { \prime \prime } ( 0 ) } { 2 ! } x ^ { 2 } + \ldots + \frac { \mathrm { f } ^ { ( r ) } ( 0 ) } { r ! } x ^ { r } + \ldots\)
\(\mathrm { e } ^ { x } = \exp ( x ) = 1 + x + \frac { x ^ { 2 } } { 2 ! } + \ldots + \frac { x ^ { r } } { r ! } + \ldots\) for all \(x\)
\(\ln ( 1 + x ) = x - \frac { x ^ { 2 } } { 2 } + \frac { x ^ { 3 } } { 3 } - \ldots + ( - 1 ) ^ { r + 1 } \frac { x ^ { r } } { r } + \ldots ( - 1 < x \leq 1 )\)
\(\sin x = x - \frac { x ^ { 3 } } { 3 ! } + \frac { x ^ { 5 } } { 5 ! } - \ldots + ( - 1 ) ^ { r } \frac { x ^ { 2 r + 1 } } { ( 2 r + 1 ) ! } + \ldots\) for all \(x\)
\(\cos x = 1 - \frac { x ^ { 2 } } { 2 ! } + \frac { x ^ { 4 } } { 4 ! } - \ldots + ( - 1 ) ^ { r } \frac { x ^ { 2 r } } { ( 2 r ) ! } + \ldots\) for all \(x\)
\(( 1 + x ) ^ { n } = 1 + n x + \frac { n ( n - 1 ) } { 2 ! } x ^ { 2 } + \ldots + \frac { n ( n - 1 ) \ldots ( n - r + 1 ) } { r ! } x ^ { r } + \ldots \quad ( | x | < 1 , n \in \mathbb { R } )\) \section*{Differentiation}
\(\mathrm { f } ( x )\)\(\mathrm { f } ^ { \prime } ( x )\)
\(\tan k x\)\(k \sec ^ { 2 } k x\)
\(\sec x\)\(\sec x \tan x\)
\(\cot x\)\(- \operatorname { cosec } ^ { 2 } x\)
\(\operatorname { cosec } x\)\(- \operatorname { cosec } x \cot x\)
\(\arcsin x\) or \(\sin ^ { - 1 } x\)\(\frac { 1 } { \sqrt { 1 - x ^ { 2 } } }\)
\(\arccos x\) or \(\cos ^ { - 1 } x\)\(- \frac { 1 } { \sqrt { 1 - x ^ { 2 } } }\)
\(\arctan x\) or \(\tan ^ { - 1 } x\)\(\frac { 1 } { 1 + x ^ { 2 } }\)
Quotient rule \(y = \frac { u } { v } , \frac { \mathrm {~d} y } { \mathrm {~d} x } = \frac { v \frac { \mathrm {~d} u } { \mathrm {~d} x } - u \frac { \mathrm {~d} v } { \mathrm {~d} x } } { v ^ { 2 } }\) \section*{Differentiation from first principles} \(\mathrm { f } ^ { \prime } ( x ) = \lim _ { h \rightarrow 0 } \frac { \mathrm { f } ( x + h ) - \mathrm { f } ( x ) } { h }\) \section*{Integration} \(\int \frac { \mathrm { f } ^ { \prime } ( x ) } { \mathrm { f } ( x ) } \mathrm { d } x = \ln | \mathrm { f } ( x ) | + c\)
\(\int \mathrm { f } ^ { \prime } ( x ) ( \mathrm { f } ( x ) ) ^ { n } \mathrm {~d} x = \frac { 1 } { n + 1 } ( \mathrm { f } ( x ) ) ^ { n + 1 } + c\)
Integration by parts \(\int u \frac { \mathrm {~d} v } { \mathrm {~d} x } \mathrm {~d} x = u v - \int v \frac { \mathrm {~d} u } { \mathrm {~d} x } \mathrm {~d} x\) The mean value of \(\mathrm { f } ( x )\) on the interval \([ a , b ]\) is \(\frac { 1 } { b - a } \int _ { a } ^ { b } \mathrm { f } ( x ) \mathrm { d } x\)
Area of sector enclosed by polar curve is \(\frac { 1 } { 2 } \int r ^ { 2 } \mathrm {~d} \theta\)
\(\mathrm { f } ( x )\)\(\int \mathrm { f } ( x ) \mathrm { d } x\)
\(\frac { 1 } { \sqrt { a ^ { 2 } - x ^ { 2 } } }\)\(\sin ^ { - 1 } \left( \frac { x } { a } \right) \quad ( | x | < a )\)
\(\frac { 1 } { a ^ { 2 } + x ^ { 2 } }\)\(\frac { 1 } { a } \tan ^ { - 1 } \left( \frac { x } { a } \right)\)
\(\frac { 1 } { \sqrt { a ^ { 2 } + x ^ { 2 } } }\)\(\sinh ^ { - 1 } \left( \frac { x } { a } \right)\) or \(\ln \left( x + \sqrt { x ^ { 2 } + a ^ { 2 } } \right)\)
\(\frac { 1 } { \sqrt { x ^ { 2 } - a ^ { 2 } } }\)\(\cosh ^ { - 1 } \left( \frac { x } { a } \right)\) or \(\ln \left( x + \sqrt { x ^ { 2 } - a ^ { 2 } } \right) \quad ( x > a )\)
\section*{Numerical methods} Trapezium rule: \(\int _ { a } ^ { b } y \mathrm {~d} x \approx \frac { 1 } { 2 } h \left\{ \left( y _ { 0 } + y _ { n } \right) + 2 \left( y _ { 1 } + y _ { 2 } + \ldots + y _ { n - 1 } \right) \right\}\), where \(h = \frac { b - a } { n }\)
The Newton-Raphson iteration for solving \(\mathrm { f } ( x ) = 0 : x _ { n + 1 } = x _ { n } - \frac { \mathrm { f } \left( x _ { n } \right) } { \mathrm { f } ^ { \prime } \left( x _ { n } \right) }\) \section*{Complex numbers} Circles: \(| z - a | = k\)
Half lines: \(\arg ( z - a ) = \alpha\)
Lines: \(| z - a | = | z - b |\) \section*{Small angle approximations} \(\sin \theta \approx \theta , \cos \theta \approx 1 - \frac { 1 } { 2 } \theta ^ { 2 } , \tan \theta \approx \theta\) where \(\theta\) is small and measured in radians \section*{Trigonometric identities} \(\sin ( A \pm B ) = \sin A \cos B \pm \cos A \sin B\)
\(\cos ( A \pm B ) = \cos A \cos B \mp \sin A \sin B\)
\(\tan ( A \pm B ) = \frac { \tan A \pm \tan B } { 1 \mp \tan A \tan B } \quad \left( A \pm B \neq \left( k + \frac { 1 } { 2 } \right) \pi \right)\) \section*{Hyperbolic functions} \(\cosh ^ { 2 } x - \sinh ^ { 2 } x = 1\)
\(\sinh ^ { - 1 } x = \ln \left[ x + \sqrt { \left( x ^ { 2 } + 1 \right) } \right]\)
\(\cosh ^ { - 1 } x = \ln \left[ x + \sqrt { \left( x ^ { 2 } - 1 \right) } \right] , x \geq 1\)
\(\tanh ^ { - 1 } x = \frac { 1 } { 2 } \ln \left( \frac { 1 + x } { 1 - x } \right) , - 1 < x < 1\)
  1. In this question you must show all stages of your working. Solutions relying entirely on calculator technology are not acceptable.
Determine the values of \(x\) for which $$64 \cosh ^ { 4 } x - 64 \sinh ^ { 2 } x - 73 = 0$$ Give your answer in the form \(q \ln 2\) where \(q\) is rational and in simplest form.
2. (a) Prove that $$\tanh ^ { - 1 } ( x ) = \frac { 1 } { 2 } \ln \left( \frac { 1 + x } { 1 - x } \right) \quad - k < x < k$$ stating the value of the constant \(k\).
(b) Hence, or otherwise, solve the equation $$2 x = \tanh ( \ln \sqrt { 2 - 3 x } )$$ [BLANK PAGE]
3. In this question you must show detailed reasoning. The roots of the equation \(x ^ { 3 } - x ^ { 2 } + k x - 2 = 0\) are \(\alpha , \frac { 1 } { \alpha }\) and \(\beta\).
(a) Evaluate, in exact form, the roots of the equation.
(b) Find \(k\).
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4. (a) (i) Given that \(f ( x ) = \sqrt { 1 + 2 x }\), find \(f ^ { \prime } ( x )\) and \(f ^ { \prime \prime } ( x )\).
(ii) Hence, find the first three terms of the Maclaurin series for \(\sqrt { 1 + 2 x }\).
(b) Hence, using a suitable value for \(x\), show that \(\sqrt { 5 } \approx \frac { 143 } { 64 }\).
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5. In this question you must show detailed reasoning.
(i) Given that $$z _ { 1 } = 6 \left( \cos \left( \frac { \pi } { 3 } \right) + i \sin \left( \frac { \pi } { 3 } \right) \right) \quad \text { and } \quad z _ { 2 } = 6 \sqrt { 3 } \left( \cos \left( \frac { 5 \pi } { 6 } \right) + i \sin \left( \frac { 5 \pi } { 6 } \right) \right)$$ show that $$z _ { 1 } + z _ { 2 } = 12 \left( \cos \left( \frac { 2 \pi } { 3 } \right) + i \sin \left( \frac { 2 \pi } { 3 } \right) \right)$$ (ii) Given that $$\arg ( z - 5 ) = \frac { 2 \pi } { 3 }$$ determine the least value of \(| \boldsymbol { z } |\) as \(Z\) varies.
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6. A curve has polar equation \(r = a ( \cos \theta + 2 \sin \theta )\), where \(a\) is a positive constant and \(0 \leq \theta \leq \pi\).
(a) Determine the polar coordinates of the point on the curve which is furthest from the pole.
(b) (i) Show that the curve is a circle whose radius should be specified.
(ii) Write down the polar coordinates of the centre of the circle.
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7. (a) It is conjectured that $$\frac { 1 } { 2 ! } + \frac { 2 } { 3 ! } + \frac { 3 } { 4 ! } + \ldots + \frac { n - 1 } { n ! } = a - \frac { b } { n ! }$$ where \(a\) and \(b\) are constants, and \(n\) is an integer such that \(n \geq 2\). By considering particular cases, show that if the conjecture is correct then $$a = b = 1$$ (b) Use induction to prove that, for \(n \geq 2\), the following is true $$\frac { 1 } { 2 ! } + \frac { 2 } { 3 ! } + \frac { 3 } { 4 ! } + \ldots + \frac { n - 1 } { n ! } = 1 - \frac { 1 } { n ! }$$ [BLANK PAGE]
8. (a) Use standard results for \(\sum _ { r = 1 } ^ { n } r ^ { 2 }\) and \(\sum _ { r = 1 } ^ { n } r\) to show that $$\sum _ { r = 1 } ^ { n } ( 3 r - 2 ) ^ { 2 } = \frac { 1 } { 2 } n \left[ 6 n ^ { 2 } - 3 n - 1 \right]$$ for all positive integers \(n\).
(b) Hence find any values of \(n\) for which $$\sum _ { r = 5 } ^ { n } ( 3 r - 2 ) ^ { 2 } + 103 \sum _ { r = 1 } ^ { 28 } r \cos \left( \frac { r \pi } { 2 } \right) = 3 n ^ { 3 }$$ [BLANK PAGE]
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