( f )
V �V � e z � w
4i t
1 2
Re ( ( )) V �V � e � e
( M1 ) for substitution
4ti 0.0571486937i
1 2
Re ( 6.991430466 ) V �V � e
( A1 ) for correct approach
4ti + 0.0571486937i
1 2
Re ( 6.991430466 ) V1� V2 � 6.991430466cos ( 4t � 0.0571486937 )
V1� V2 � 6.99cos ( 4t � 0.0571 )
A1
( g ) The required total voltage �6.991430466cos ( 4 ( 1 ) � 0.0571486937 ) ( M1 ) for substitution �� 4.260226648 V �� 4.26 V
A1
[ 3 ]
[ 2 ]
Exercise 24
6
1 . Two sound waves are given as S1 �2sin ( 6t� 0.1 ) and S2 �3sin ( 6t� 0.25 ) respectively ,
where S
1
and S
2 represent the amplitudes of the two sound waves respectively , in millimetres , and t represents time in seconds . The total amplitude S is given by S �S1� S2.
( a ) Write down the amplitude of
( i ) S
1
;
( ii ) S
2
.
( b ) Find the period of S
2
.
It is given that
S � S � e z � w , z , w� .
6i t
1 2
Im ( ( ))
( c ) Find the expression of z� w.
( d ) Express the following in the form r( cos�
� isin �) :
[ 2 ]
[ 2 ]
[ 3 ]
( i ) z
( ii ) w [ 2 ] www . seprodstore . com
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