Sum of first n terms 0f an A.P.is n /2(3n+13)find 30th term
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nth term n/2(3n+13)
so 1st term 1/2(3×1+13)=8
sum of 2nd term 2/2(3×2+13)=19
sum of 3rd term 3/2(3×3+13)=33
sum of 4th term 4/2(3×4+13)=50
so 1st term 8
2nd term=19-8=11
3rd term=33-19=14
4th term=17........nd so on
so 30th term=a+(n-1)d
=8+29×3=95
so 1st term 1/2(3×1+13)=8
sum of 2nd term 2/2(3×2+13)=19
sum of 3rd term 3/2(3×3+13)=33
sum of 4th term 4/2(3×4+13)=50
so 1st term 8
2nd term=19-8=11
3rd term=33-19=14
4th term=17........nd so on
so 30th term=a+(n-1)d
=8+29×3=95
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