Question

What is the value........

Answer 1

`a_5 = 120`

Explanation:

Given

`a_1 = 1`

`a_n = n(a_(n-1))`

Required

`a_5`

This is calculated as:

`a_5 = 5(a_(5-1))`

`a_5 = 5*a_4`

Calculate
`a_4`

`a_4 =4(a_(4-1))`

`a_4 =4*a_3`

Calculate
`a_3`

`a_3 =3*a_2`

Calculate
`a_2`

`a_2 = 2 * a_1`

`a_2 = 2 * 1`

`a_2 = 2`

So:

`a_3 =3*a_2`

`a_3 = 3 * 2 = 6`

So:

`a_4 =4*a_3`

`a_4 = 4 * 6 =24`

Lastly;

`a_5 = 5*a_4`

`a_5 = 5 * 24`

`a_5 = 120`