Math, asked by ThanuCL, 1 year ago

How many terms of the sequence 18,16,14 - - - - should be taken so that there sum is zero

Answers

Answered by Panzer786
23
Heya !!!



AP = 18 , 16 , 14 .....



Here,


First term ( A ) = 18


Common Difference ( D ) = 16-18 = -2



Sn = 0


N/2 × [ 2A + ( N - 1 ) × D ] = 0



N/2 × [ 2 × 18 + ( N - 1 ) × -2 ] = 0



N/2 × ( 36 - 2N + 2 ) = 0



N/2 × 38 - 2N = 0



N/2 × 2 ( 19 - N ) = 0



-N² + 19N = 0


N ( - n + 19 ) = 0



- n + 19 = 0



- n = -19


n = 19



Hence,


19 terms should be taken to get their sum as 0.



★ HOPE IT WILL HELP YOU ★
Similar questions