1.

If `[cot^(-1)x]+[cos^(-1)x]=0`, where `[]`denotes the greatest integer functions, then the complete set of valuesof `x`is`(cos1,1)`(b) `cos1,cos1)``(cot1,1)`(d) none of theseA. `(cos 1,1]`B. `(cos 1, cot1)`C. `(cot 1, 1]`D. none of these

Answer» We have
`cot^(-1) x in [0,pi] and cos^(-1) x in [0,pi]`
`therefore [cost(-1)x]gt0 and [cos^(-1)x]ge0`
Now `[cos^(-1)x]=0 =[cos^(-1)xlt1`
`rarr cot 1 ltx lt infty and cos 1 lt x le 1`
`rarr fx in (cot1,infty) and x in (cos 1,1]rarr x in (cot1,1]`


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