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The value of sin{cot^(-1)[cos(cot^(-1)((...

The value of `sin{cot^(-1)[cos(cot^(-1)((1)/(x)))]}` is equal to `(x gt0)`

A

`sqrt((1+x^(2))/(2+x^(2)))`

B

`sqrt((1-x^(2))/(2+x^(2)))`

C

`sqrt((1+x^(2))/(2-x^(2)))`

D

`sqrt((2+x^(2))/(1+x^(2)))`

Text Solution

AI Generated Solution

The correct Answer is:
To solve the problem, we need to find the value of \( \sin\left(\cot^{-1}\left[\cos\left(\cot^{-1}\left(\frac{1}{x}\right)\right)\right]\right) \) for \( x > 0 \). ### Step-by-Step Solution: 1. **Let \( \alpha = \cot^{-1}\left(\frac{1}{x}\right) \)**: - By definition, \( \cot(\alpha) = \frac{1}{x} \). - This implies \( x = \frac{1}{\cot(\alpha)} = \tan(\alpha) \). **Hint**: Remember that \( \cot^{-1}(y) \) gives an angle whose cotangent is \( y \). 2. **Find \( \cos(\alpha) \)**: - In a right triangle where \( \tan(\alpha) = x \), we can represent the sides as follows: - Opposite side = \( x \) - Adjacent side = \( 1 \) - Using the Pythagorean theorem, the hypotenuse \( h \) is given by: \[ h = \sqrt{x^2 + 1^2} = \sqrt{1 + x^2} \] - Therefore, \( \cos(\alpha) = \frac{\text{Adjacent}}{\text{Hypotenuse}} = \frac{1}{\sqrt{1 + x^2}} \). **Hint**: Use the triangle relationships to find cosine based on tangent. 3. **Now find \( \cot^{-1}(\cos(\alpha)) \)**: - We have \( \cos(\alpha) = \frac{1}{\sqrt{1 + x^2}} \). - Let \( \beta = \cot^{-1}\left(\frac{1}{\sqrt{1 + x^2}}\right) \). - This means \( \cot(\beta) = \frac{1}{\sqrt{1 + x^2}} \). **Hint**: Recognize that \( \cot^{-1}(y) \) gives an angle whose cotangent is \( y \). 4. **Find \( \sin(\beta) \)**: - In a right triangle where \( \cot(\beta) = \frac{1}{\sqrt{1 + x^2}} \): - Opposite side = \( 1 \) - Adjacent side = \( \sqrt{1 + x^2} \) - The hypotenuse \( h \) is given by: \[ h = \sqrt{1^2 + \left(\sqrt{1 + x^2}\right)^2} = \sqrt{1 + (1 + x^2)} = \sqrt{2 + x^2} \] - Therefore, \( \sin(\beta) = \frac{\text{Opposite}}{\text{Hypotenuse}} = \frac{1}{\sqrt{2 + x^2}} \). **Hint**: Again, use the triangle relationships to find sine based on cotangent. 5. **Final Result**: - Thus, we have: \[ \sin\left(\cot^{-1}\left[\cos\left(\cot^{-1}\left(\frac{1}{x}\right)\right)\right]\right) = \frac{1}{\sqrt{2 + x^2}} \] ### Conclusion: The value of \( \sin\left(\cot^{-1}\left[\cos\left(\cot^{-1}\left(\frac{1}{x}\right)\right)\right]\right) \) is \( \frac{1}{\sqrt{2 + x^2}} \) for \( x > 0 \).
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Knowledge Check

  • The value of sin(cot^(-1) (cos (tan^(-1)x))) is

    A
    `sqrt((x^(2) + 2)/(x^(2) + 1))`
    B
    `sqrt((x^(2) + 1)/(x^(2) + 2))`
    C
    `x/sqrt(x^(2) + 2)`
    D
    `1/sqrt(x^(2) + 2)`
  • The value of sin[cot^(-1){cos(tan^(-1) x)}] is

    A
    `sqrt(x^(2)+2)/(sqrt(x^(2)+1)`
    B
    `sqrt(x^(2)+1)/(sqrt(x^(2)+2)`
    C
    `(x)/sqrt(x^(2)+2)`
    D
    `(1)/sqrt(x^(2)+2)`
  • sin{cot^(-1)[cos(tan^(-1)x)]}=....

    A
    `sqrt((x^(2)+2)/(x^(2)+1))`
    B
    `sqrt((x^(2)+1)/(x^(2)+2))`
    C
    `sqrt(x^(2)+1)`
    D
    none of these
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