tn=6n+5 then ans sn=?
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Tn = 6n +5
=> a +(n-1)d = 6n +5
=> a +(n-1)d = 11 + 6n - 6
=> a +(n-1)d = 11+ 6(n-1)
Comparing both sides, we get
a= 11
d = 6
Sn = n/2 [ a + Tn]
= (n/2) ( 11+6n +5)
= (n/2) (6n +16)
= n(3n + 8)
= 3n^2 + 8n
=> a +(n-1)d = 6n +5
=> a +(n-1)d = 11 + 6n - 6
=> a +(n-1)d = 11+ 6(n-1)
Comparing both sides, we get
a= 11
d = 6
Sn = n/2 [ a + Tn]
= (n/2) ( 11+6n +5)
= (n/2) (6n +16)
= n(3n + 8)
= 3n^2 + 8n
Answered by
31
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