Analysis and Approaches for IBDP Maths Ebook 2 | Page 225
a � 3tan( �3 t � C)
A1
3 � 3tan( �3(0) � C)
(M1) for substitution
3
� tan C
3
�
tan C � tan 6
(b)
C � �
6
(A1) for correct value
� � �
�a� 3tan ��3t�
�
� 6 �
A1
dv
� � �
� 3tan ��3t
� �
dt
� 6�
� � �
3sin ��3t
� �
6
dv�
� �
dt
� � �
cos��3t
� �
� 6 �
� � �
3sin ��3t
� �
6
dv
� �
� � � dt
(A1) for correct approach
� � �
cos��3t
� �
� 6 �
� � �
Let u � cos��3t�
�. (M1) for substitution
� 6 �
du
� � � � � �
� �3sin ��3t � � �3sin ��3t � �dt � �1�du
dt
� 6 � � 6 �
1
� dv� � du
u
v � �lnu � D
� � (A1) for correct working
� � �
v � �ln cos ��3t � � � D
� 6 �
A1
[7]
15
3 � � �
�ln � �ln cos��3(0)
� � � D
2 � 6�
(M1) for substitution
3 3
�ln
� �ln
� D
2 2
D � 0
(A1) for correct value
� � �
�v� �ln cos ��3t�
�
� 6 �
A1
[7]
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