i want to know the solving method of the ques no 8 briefly
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Solution :
Sum of t terms St = 3t² + 4t
i ) First term = a = S1 = 3 + 4 = 7
ii ) S2 = 3(2²) + 4×2 = 12 + 8 = 20
iii ) Second term ( a2 ) = S2 - S1
= 20 - 7
= 13
iv ) Common difference (d) = a2 - a1
= 13 - 7
= 6
Now ,
nth term of an A.P = an
= a + ( n-1 )d
= 7 + ( n - 1 )6
= 7 + 6n - 6
= 6n + 1
Therefore ,
n th term of an A.P = an = 6n + 1
•••••
Sum of t terms St = 3t² + 4t
i ) First term = a = S1 = 3 + 4 = 7
ii ) S2 = 3(2²) + 4×2 = 12 + 8 = 20
iii ) Second term ( a2 ) = S2 - S1
= 20 - 7
= 13
iv ) Common difference (d) = a2 - a1
= 13 - 7
= 6
Now ,
nth term of an A.P = an
= a + ( n-1 )d
= 7 + ( n - 1 )6
= 7 + 6n - 6
= 6n + 1
Therefore ,
n th term of an A.P = an = 6n + 1
•••••
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