COMEDK202510 May 2025Morning ShiftMathematicsInverse Trigonometric FunctionsActual
The range of x for which the equation ⁻¹ ( 2 x 1+x^2 )=2 ⁻¹ x holds true
Options
- Ax 0
- Bx R
- C|x| 1
- D|x| 1
Correct answer
D. |x| 1
Step-by-step solution
The expression ⁻¹ ( 2x 1+x^2 ) is defined for | 2x 1+x^2 | 1 , which implies 2|x| 1+x^2 , or (|x|-1)^2 0 , which is true for all x R . Recall the identity ⁻¹ ( 2x 1+x^2 ) = 2 ⁻¹ x for |x| 1 . For x > 1 , let x = where ( /4, /2) . Then 2x 1+x^2 = (2 ) . Since 2 ( /2, ) , ⁻¹( (2 )) = - 2 = - 2 ⁻¹ x . Thus, the identity does not hold for x > 1 . For x Therefore, the equation holds true if and only if |x| 1 . Answer: |x| 1