Question

Expand.

`(1 - 1/a)^3`

Answer 1

`(1 - 1/a)^3`

(a − b)³ = a³ − 3a²b + 3ab² − b³

her taking a = 1 and b = `(1/a)`

= `(1)^3  - 3 xx (1)^2 xx (1/a) + 3 xx 1 xx (1/a)^2 - (1/a)^3`

= `1 - 3 xx 1/a + 3 xx 1/a^2 - 1/a^3`

= `1 - 3/a + 3/a^2 - 1/a^3`