which term of sequence 4,9,14,19........124.determine 15th term and sum of the AP
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Dear mate,. Here's your answer...
First term a = 4
Common difference d = (a2 - a1) = ( 9 - 4 ) = 5
No. of term = 15
nth term a15 = ?
an = a + ( n - 1 )d
= 4 + ( 15 - 1 )5
= 4 + 70
= 74
Sum of terms. S15 = ?
Sn = [n/2 ( 2a + ( n - 1 )d]
S15 = 15/2 ( 2 × 4 + ( 15 - 1 ) 5
= 15/2 ( 8 + 70 )
= 15 / 2 × 78
15 × 39 = 585
Hope it helps you !!
First term a = 4
Common difference d = (a2 - a1) = ( 9 - 4 ) = 5
No. of term = 15
nth term a15 = ?
an = a + ( n - 1 )d
= 4 + ( 15 - 1 )5
= 4 + 70
= 74
Sum of terms. S15 = ?
Sn = [n/2 ( 2a + ( n - 1 )d]
S15 = 15/2 ( 2 × 4 + ( 15 - 1 ) 5
= 15/2 ( 8 + 70 )
= 15 / 2 × 78
15 × 39 = 585
Hope it helps you !!
pavan567:
hi
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