1.

which term of the A.P. : 120, 116, 112,..... is first negative term?

Answer» In the given `A.P.`,
First term, `a = 120`
Common difference `d = -4`
`:. T_n = a+(n-1)d = 120 - 4(n-1) = 124-4n`
For, `T_n` to be negative,
`124-4n lt 0`
`=> 4n gt 124 => n gt 31`
So, for `n = 32`, `T_n` will be negative.
So, `32^(nd)` term of the given `A.P.` will be the first negative term.


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