Question

find the 9th term of the arithmetic progression 1,3,5,6,8.5_?​

Answer 1

Answer:

9 is the ninetheenth term of arthematic.

Answer 2

Answer:

The 9 th term is 17.

Step-by-step explanation:

Given,

1,3,5,6,8.5_

This series in Arithmetic progression

We know, n th term, aₙ = a₁ + (n − 1)d Where a₁ is term of the series and d common difference.

Now 9 th term ,

$a_9 = a_1+(n-1)d= 1 + (9 - 1) \times 2 = 1 + 8 \times 2 = 1 + 16 = 17$

There 9 th term is 17

Other formula of this series are

$S_n= \frac{n}{2} [2a + (n - 1)d]$