CAIE
FP1
2014
June
Q9
10 marks
Standard +0.3
9 The matrix \(\mathbf { M }\), where
$$\mathbf { M } = \left( \begin{array} { r r r }
- 2 & 2 & 2 \\
2 & 1 & 2 \\
- 3 & - 6 & - 7
\end{array} \right)$$
has an eigenvector \(\left( \begin{array} { r } 0 \\ 1 \\ - 1 \end{array} \right)\). Find the corresponding eigenvalue.
It is given that if the eigenvalues of a general \(3 \times 3\) matrix \(\mathbf { A }\), where
$$\mathbf { A } = \left( \begin{array} { l l l }
a & b & c \\
d & e & f \\
g & h & i
\end{array} \right)$$
are \(\lambda _ { 1 } , \lambda _ { 2 }\) and \(\lambda _ { 3 }\) then
$$\lambda _ { 1 } + \lambda _ { 2 } + \lambda _ { 3 } = a + e + i$$
and the determinant of \(\mathbf { A }\) has the value \(\lambda _ { 1 } \lambda _ { 2 } \lambda _ { 3 }\).
Use these results to find the other two eigenvalues of the matrix \(\mathbf { M }\), and find corresponding eigenvectors.
CAIE
FP1
2014
June
Q11
11 marks
Challenging +1.2
11 The line \(l _ { 1 }\) passes through the points \(A ( 2,3 , - 5 )\) and \(B ( 8,7 , - 13 )\). The line \(l _ { 2 }\) passes through the points \(C ( - 2,1,8 )\) and \(D ( 3 , - 1,4 )\). Find the shortest distance between the lines \(l _ { 1 }\) and \(l _ { 2 }\).
The plane \(\Pi _ { 1 }\) passes through the points \(A , B\) and \(D\). The plane \(\Pi _ { 2 }\) passes though the points \(A , C\) and \(D\). Find the acute angle between \(\Pi _ { 1 }\) and \(\Pi _ { 2 }\), giving your answer in degrees.
CAIE
FP1
2014
June
Q3
7 marks
Standard +0.3
3
- 2
0
\end{array} \right) .$$
Show that \(\{ \mathbf { a } , \mathbf { b } , \mathbf { c } \}\) is a basis for \(\mathbb { R } ^ { 3 }\).
Express \(\mathbf { d }\) in terms of \(\mathbf { a } , \mathbf { b }\) and \(\mathbf { c }\).
2 Show that the difference between the squares of consecutive integers is an odd integer.
Find the sum to \(n\) terms of the series
$$\frac { 3 } { 1 ^ { 2 } \times 2 ^ { 2 } } + \frac { 5 } { 2 ^ { 2 } \times 3 ^ { 2 } } + \frac { 7 } { 3 ^ { 2 } \times 4 ^ { 2 } } + \ldots + \frac { 2 r + 1 } { r ^ { 2 } ( r + 1 ) ^ { 2 } } + \ldots$$
and deduce the sum to infinity of the series.
3 It is given that \(\phi ( n ) = 5 ^ { n } ( 4 n + 1 ) - 1\), for \(n = 1,2,3 , \ldots\). Prove, by mathematical induction, that \(\phi ( n )\) is divisible by 8 , for every positive integer \(n\).
CAIE
FP1
2014
June
Q7
10 marks
Standard +0.3
7 The curve \(C\) has parametric equations
$$x = \sin t , \quad y = \sin 2 t , \quad \text { for } 0 \leqslant t \leqslant \pi .$$
Find \(\frac { \mathrm { d } ^ { 2 } y } { \mathrm {~d} x ^ { 2 } }\) in terms of \(t\).
Hence, or otherwise, find the coordinates of the stationary points on \(C\) and determine their nature.
CAIE
FP1
2014
June
Q9
10 marks
Challenging +1.2
9 Using the substitution \(u = \cos \theta\), or any other method, find \(\int \sin \theta \cos ^ { 2 } \theta d \theta\).
It is given that \(I _ { n } = \int _ { 0 } ^ { \frac { 1 } { 2 } \pi } \sin ^ { n } \theta \cos ^ { 2 } \theta \mathrm {~d} \theta\), for \(n \geqslant 0\). Show that, for \(n \geqslant 2\),
$$I _ { n } = \frac { n - 1 } { n + 2 } I _ { n - 2 }$$
Hence find the exact value of \(\int _ { 0 } ^ { \frac { 1 } { 2 } \pi } \sin ^ { 4 } \theta \cos ^ { 2 } \theta d \theta\).
CAIE
FP1
2014
June
Q10
12 marks
Challenging +1.2
10 Find the particular solution of the differential equation
$$\frac { \mathrm { d } ^ { 2 } x } { \mathrm {~d} t ^ { 2 } } + 0.16 \frac { \mathrm {~d} x } { \mathrm {~d} t } + 0.0064 x = 8.64 + 0.32 t$$
given that when \(t = 0 , x = 0\) and \(\frac { \mathrm { d } x } { \mathrm {~d} t } = 0\).
Show that, for large positive \(t , \frac { \mathrm {~d} x } { \mathrm {~d} t } \approx 50\).