If sn the sum of first n terms of an ap is given by sn=5nsquare+3n find nth term smart guy shuld answr
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Sn=5n²+3n,
then
S1=5(1)²+3×1=8=a,
S2=5(2)²+3×2=20+6=26,
then
[2/2{2×8+(2-1)d}]=26,
[16+d]=26,
d=26-16=10,
hence
tn=a+(n-1)d,
tn=8+(n-1)10,
tn=8+10n-10,
tn=10n-2,
tn=2(5n-1)
then
S1=5(1)²+3×1=8=a,
S2=5(2)²+3×2=20+6=26,
then
[2/2{2×8+(2-1)d}]=26,
[16+d]=26,
d=26-16=10,
hence
tn=a+(n-1)d,
tn=8+(n-1)10,
tn=8+10n-10,
tn=10n-2,
tn=2(5n-1)
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