1.

If three successive terms of as G.P. with commonratio `rgt1` form the sides of a triangle and [r] denotes the integral part of x the `[r]+[-r]=` (A) 0 (B) 1 (C) -1 (D) none of these

Answer» Correct Answer - C
Let the sides of a triangle be `a,ar,ar^(2)`.
Since, `rgt1`. Therefore, `ar^(2)` is the largest side.
`:." "a+argtar^(2)`
`rArr" "ar^(2)-a-arlt0`
`rArr" "r^(2)-r=1lt0`
`rArr" "(1-sqrt(5))/(2)ltrlt(1+sqrt(5))/(2)`
`rArr" "1ltrlt(1+sqrt(5))/(2)rArr[r]=1" "[becausergt1]`
Also,
`-(1+sqrt(5))/(2)lt-rlt-1rArr[-r]=-2`
Hence, [r]+[-r]=1-2=-1.


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