the sum of the n terms if an Ap is 5n2-3n. find the nth term and 10th term
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4
the required a. p is 2,12,22,.............
Answered by
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Sn= 5n^2-3n
S1= 5(1)^2-3(1)
= 5-3
=2
S2=5(2)^2-3(2)
=5(4)-6
=20-6
=14
S2-S1=d
14-2=d
d=12
t10=a+9d
= 2+9(12)
=2+108
=110
S1= 5(1)^2-3(1)
= 5-3
=2
S2=5(2)^2-3(2)
=5(4)-6
=20-6
=14
S2-S1=d
14-2=d
d=12
t10=a+9d
= 2+9(12)
=2+108
=110
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