Q3 / 71 · NTA Abhyas (JEE Main) 2020 · Mathematics · Inverse Trigonometric Functions

The value of sincot-1coscot-11x is equal to x>0

  • Correct answer
    A
    1+x22+x2
  • B
    1-x22+x2
  • C
    1+x22-x2
  • D
    2+x21+x2

Solution

Let cot-11x=α⇒ tan⁡α= x
So, cos⁡α=11+x2
∴ sin⁡cot-1⁡cos⁡tan-1⁡x
= sincot-111+x2
Let cot-111+x2=β⇒ cot⁡β=11+x2
∴sin⁡β=(1+x2)(2+x2)
∴sin⁡β=sin⁡cot-1cos⁡cot-1⁡1x=1+x22+x2

Hence, the correct answer is option: 'A'.

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