Your Practice Set – Applications and Interpretation for IBDP Mathematics
Exercise 11
1 . The first three terms of a geometric sequence are u1 �� 900 , u2 �� 540 and u3 �� 324.
( a ) Find the value of r .
( b ) Find the value of S
10
.
( c ) Find the sum to infinity of this sequence .
[ 2 ]
[ 2 ]
[ 2 ]
2 . The first three terms of an infinite geometric sequence are x � 0 .
48 ln x ,
24 ln x and
12 ln x , where
( a ) Find the common ratio of the geometric sequence .
( b ) Find u
6
.
( c ) Find the sum to infinity of this sequence .
[ 3 ]
[ 2 ]
[ 2 ]
3 . The first three terms of an infinite geometric sequence are
( a ) Find the common ratio of the geometric sequence .
( b ) Find u
7
.
( c ) Find x if the sum to infinity of this sequence is e
12x
e ,
96
8x
e and
4x
e .
[ 2 ]
[ 2 ]
24 e � 1 . [ 3 ]
4 . The first three terms of an infinite geometric sequence are
10
3 x ,
9
3 x and
8
3 x .
( a ) Find the common ratio of the geometric sequence .
( b ) Find a general expression for u n
.
[ 2 ]
[ 3 ] ( c ) Find the sum to infinity if the common ratio is 1 , giving the answer in the form
3
a� 3 b . [ 3 ]
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