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If `sin^(-1)(x-1)+cos^(-1)(x-3)+tan^(-1)(x/(2-x^2))=cos^(-1)k+pi,`then the value of `k`isA. 1B. `-(1)/(sqrt2)`C. `(1)/(sqrt2)`D. none of these |
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Answer» Correct Answer - C `sin^(-1) (x -1)` `rArr -1 le x -1 le 1` `rArr 0 le x le 2` `cos^(-1) (x -3)` `rArr -1 le x -3 le 1` `rArr 2 le x le 4` `:. X = 2` So, `sin^(-1) (2 -1) + cos^(-1) (2 -3) + tan^(-1).(2)/(2 -4) = cos^(-1) k + pi` or `sin^(-1) 1 + cos^(-1) (-1) + tan^(-1) (-1) = cos^(-1) + pi` `rArr (pi)/(2) + pi - (pi)/(4) = cos^(-1) k + pi` `rArr cos^(-1) k = (pi)/(4) " or " k = (1)/(sqrt2)` |
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