1.

The number of solutions of `|[x]-2x|=4, "where" [x]]` is the greatest integer less than or equal to x, isA. infiniteB. 4C. 3D. 2

Answer» Correct Answer - A
We have `|[x]-2x|=4`
`implies|[x]-2([x]+{x})|=4`
`implies|[x]+2{x}|=4`
which is possible only when
`2{x}=0,1`
If `{x}=0 then `[x]=+-4` and then `x=-4,4` and if `{x}=1/2`, then
`[x]+1=+-4`
`implies[x]=3,-5`
`:.x=3+1/2` and `-5+1/2`
`impliesx=7/2,-9/2impliesx=-4, -9/2,7/2,4`


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