Answers

2014-03-12T12:50:18+05:30
T4=3*t1
t7=1+t3
so 
a+3d=3a.......................1
a+6d=1+a+2d.....................2
2a=3d
4d=1
so d=1/4
2a=3/4
a=3/8
s0
3/8,5/8,7/8,9/8,....................
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2014-03-12T16:08:22+05:30
Let the first term be a and common difference be d
according to the question
t₄=3*t₁
a+3d=3a
2a-3d=0.............1

t₇=2t₃+1
a+6d=2(a+2d)+1
a+6d=2a+4d+1
a-2d=1..............2

on solving 1 and 2
we get 
a=3 and d=2
therefore the sequence is 3,5,7,9.................
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