5 . An arithmetic sequence has the first term ln 0.25 and a common difference ln D , where D � 0 . The 9th term in the sequence is 6ln 2 .
( a ) Find the value of D . [ 5 ]
( b ) Hence , find the sum of the first seven terms , giving the answer in the form a ln 2 .
[ 3 ]
© SE Production Limited 8 All Rights Reserved 2021