A sequence is defined by `a_n=n^3-6n^2+11 n-6.` Show that the first three terms of the sequence are zero and all other terms are positive.

Explanation

Given,

`a_n​=n^3−6n^2+11n−6`


Putting `n=1,2,3` we get


`a_1=(1)^3−6xx1^2+11xx1−6
=1−6+11−6=12−12=0`


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