the sum of first n terms of an AP is given by sn=4n2-3n, find the nth term of an AP
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use this formula to find out answer
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sn=4n^2-3n
sn-1=4(n-1)^2-3(n-1)
sn-1=4(n^2-2n+1)-3n+3
sn-1=4n^2-8n+4-3n+3
sn-1=4n^2-11n+7
WE KNOW THAT,
tn=sn-sn-1
tn=(4n^2-3n)-(4n^2-11n+7)
tn=4n^2-3n-4n^2+11n-7
tn=8n-7
Therefore the nth term whose sn=4n^2-3n is 8n-7
sn-1=4(n-1)^2-3(n-1)
sn-1=4(n^2-2n+1)-3n+3
sn-1=4n^2-8n+4-3n+3
sn-1=4n^2-11n+7
WE KNOW THAT,
tn=sn-sn-1
tn=(4n^2-3n)-(4n^2-11n+7)
tn=4n^2-3n-4n^2+11n-7
tn=8n-7
Therefore the nth term whose sn=4n^2-3n is 8n-7
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