OCR Further Additional Pure Specimen — Question 5 9 marks

Exam BoardOCR
ModuleFurther Additional Pure (Further Additional Pure)
SessionSpecimen
Marks9
PaperDownload PDF ↗
Mark schemeDownload PDF ↗
TopicReduction Formulae
TypeTrigonometric power reduction
DifficultyChallenging +1.3 This is a standard reduction formula question from Further Maths requiring integration by parts to derive the recurrence relation, then applying it systematically. While it requires careful algebraic manipulation and multiple steps, the technique is well-practiced in Further Maths courses and follows a predictable pattern. The twist of converting cos²θ sin⁵θ using the identity adds modest complexity but remains within standard Further Maths territory.
Spec1.08c Integrate e^(kx), 1/x, sin(kx), cos(kx)8.06a Reduction formulae: establish, use, and evaluate recursively

5 In this question you must show detailed reasoning.
It is given that \(I _ { n } = \int _ { 0 } ^ { \pi } \sin ^ { n } \theta \mathrm {~d} \theta\) for \(n \geq 0\).
  1. Prove that \(I _ { n } = \frac { n - 1 } { n } I _ { n - 2 }\) for \(n \geq 2\).
  2. (a) Evaluate \(I _ { 1 }\).
    (b) Use the reduction formula to determine the exact value of \(\int _ { 0 } ^ { \pi } \cos ^ { 2 } \theta \sin ^ { 5 } \theta \mathrm {~d} \theta\).

Question 5:
AnswerMarks Guidance
5(i) DR
I (cid:32)(cid:179) (cid:83) sin(cid:84).sinn(cid:16)1(cid:84)d(cid:84)
n
0
(cid:83)
(cid:32)(cid:170)– cos(cid:84). sinn–1(cid:84)(cid:186) (cid:16)
(cid:172) (cid:188)
0
(cid:83)
...(cid:179) (cid:16)cos(cid:84).(n(cid:16)1)sinn(cid:16)2(cid:84).cos(cid:84)d(cid:84)
0
(cid:83)(cid:11) (cid:12)
(cid:32)0(cid:14)(cid:11)n(cid:16)1(cid:12)(cid:180) (cid:181) 1(cid:16)sin2(cid:84) sinn(cid:16)2(cid:84)d(cid:84)
(cid:182)
0
(cid:32) (cid:11) n(cid:16)1(cid:94)I (cid:16)I (cid:96)(cid:12)
n(cid:16)2 n
n(cid:16)1
(cid:159)I (cid:32) I
n n(cid:16)2
AnswerMarks
nM1
A1
M1
A1
E1
AnswerMarks
[5]2.1
1.1
2.1
1.1
AnswerMarks
1.1Correct splitting and attempt at (cid:179)n by
parts
n
Use of trigonometric identity in order
e
to obtain …
... substitution for I
m
AG
AnswerMarks Guidance
5(ii) (a)
(cid:83)
I (cid:32)(cid:179) sin(cid:84)d(cid:84)
1
0
AnswerMarks
= 2M1
e
A1
AnswerMarks
[2]i
c
3.1a
1.1
AnswerMarks Guidance
5(ii) (b)
DR
S
Using c2 (cid:32)1(cid:16)s2, I (cid:32)I (cid:16)I
5 7
I (cid:16)I (cid:32) (cid:11) 1(cid:16)6(cid:12) I (cid:32)1(cid:117)4I
5 7 7 5 7 5 3
(cid:32) 1(cid:117)4(cid:117)2I (cid:32) 16
AnswerMarks
7 5 3 1 105M1
E1
AnswerMarks
[2]3.1a
2.1Repeated use of RF soi
Correct answer with sufficient detail to
show the reduction process
Question 5:
5 | (i) | DR
I (cid:32)(cid:179) (cid:83) sin(cid:84).sinn(cid:16)1(cid:84)d(cid:84)
n
0
(cid:83)
(cid:32)(cid:170)– cos(cid:84). sinn–1(cid:84)(cid:186) (cid:16)
(cid:172) (cid:188)
0
(cid:83)
...(cid:179) (cid:16)cos(cid:84).(n(cid:16)1)sinn(cid:16)2(cid:84).cos(cid:84)d(cid:84)
0
(cid:83)(cid:11) (cid:12)
(cid:32)0(cid:14)(cid:11)n(cid:16)1(cid:12)(cid:180) (cid:181) 1(cid:16)sin2(cid:84) sinn(cid:16)2(cid:84)d(cid:84)
(cid:182)
0
(cid:32) (cid:11) n(cid:16)1(cid:94)I (cid:16)I (cid:96)(cid:12)
n(cid:16)2 n
n(cid:16)1
(cid:159)I (cid:32) I
n n(cid:16)2
n | M1
A1
M1
A1
E1
[5] | 2.1
1.1
2.1
1.1
1.1 | Correct splitting and attempt at (cid:179)n by
parts
n
Use of trigonometric identity in order
e
to obtain …
... substitution for I
m
AG
5 | (ii) | (a) | DR
(cid:83)
I (cid:32)(cid:179) sin(cid:84)d(cid:84)
1
0
= 2 | M1
e
A1
[2] | i
c
3.1a
1.1
5 | (ii) | (b) | p
DR
S
Using c2 (cid:32)1(cid:16)s2, I (cid:32)I (cid:16)I
5 7
I (cid:16)I (cid:32) (cid:11) 1(cid:16)6(cid:12) I (cid:32)1(cid:117)4I
5 7 7 5 7 5 3
(cid:32) 1(cid:117)4(cid:117)2I (cid:32) 16
7 5 3 1 105 | M1
E1
[2] | 3.1a
2.1 | Repeated use of RF soi
Correct answer with sufficient detail to
show the reduction process
5 In this question you must show detailed reasoning.\\
It is given that $I _ { n } = \int _ { 0 } ^ { \pi } \sin ^ { n } \theta \mathrm {~d} \theta$ for $n \geq 0$.
\begin{enumerate}[label=(\roman*)]
\item Prove that $I _ { n } = \frac { n - 1 } { n } I _ { n - 2 }$ for $n \geq 2$.
\item (a) Evaluate $I _ { 1 }$.\\
(b) Use the reduction formula to determine the exact value of $\int _ { 0 } ^ { \pi } \cos ^ { 2 } \theta \sin ^ { 5 } \theta \mathrm {~d} \theta$.
\end{enumerate}

\hfill \mbox{\textit{OCR Further Additional Pure  Q5 [9]}}