InterviewSolution
Saved Bookmarks
InterviewSolution
| 1. |
If `cos^-1 (x^2-1)/(x^2+1)+ tan^-1 (2x)/(x^2-1) = (2pi)/3`, then x equal to (A) `sqrt(3)` (B) `2+sqrt(3)` (C) `2-sqrt(3)` (D) `-sqrt(3)`A. 2B. `sqrt(3)`C. 4D. 3 |
|
Answer» Correct Answer - B `cos^(-1)((x^(2)-1)/(x^(2)+1))=pi - co^(-1)((1-x^(2))/(1+x^(2)))=pi-2 tan^(-1)x` (as x gt 1) `tan^(-1)((2x)/(x^(2)-1))=-tan^(-1)((2x)/(1-x^(2)))=pi-2 tan^(-1)x` (as x gt 1) `therefore` Given equation is `2pi-4 tan^(-1)x = 2pi//3` `therefore tan^(-1)x = pi//3` `therefore x = sqrt(3)` |
|