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Statement I: The equation ("sin"^-1x)^3 ...

Statement I: The equation `("sin"^-1x)^3 +("cos"^-1x)^3 -api^(3)=0` has a solution for all a> `(1)/(32)`
Statement II: for any X `epsilon R` ,`"sin"^-1x+"cos"^(-1)x=(pi)/(2)` and `0<("sin" x-(pi)/(4))^2 < (9pi^2)/(16)`

A

Both statements I and II are true

B

Both statements I and II are False

C

Statement I is true and statement II is false.

D

Statement I is true and statement II is true.

Text Solution

AI Generated Solution

The correct Answer is:
To solve the problem, we need to analyze both statements provided and verify their correctness step by step. ### Step 1: Analyze Statement I The equation given is: \[ (\sin^{-1} x)^3 + (\cos^{-1} x)^3 - a \pi^3 = 0 \] We can rewrite this as: \[ (\sin^{-1} x)^3 + (\cos^{-1} x)^3 = a \pi^3 \] ### Step 2: Use the identity for inverse trigonometric functions We know that: \[ \sin^{-1} x + \cos^{-1} x = \frac{\pi}{2} \] Let \( y = \sin^{-1} x \). Then, we have: \[ \cos^{-1} x = \frac{\pi}{2} - y \] ### Step 3: Substitute into the equation Substituting into our equation gives: \[ y^3 + \left(\frac{\pi}{2} - y\right)^3 = a \pi^3 \] ### Step 4: Expand the cube Expanding the second term: \[ \left(\frac{\pi}{2} - y\right)^3 = \frac{\pi^3}{8} - \frac{3\pi^2}{4}y + \frac{3\pi}{2}y^2 - y^3 \] Thus, we can rewrite the equation as: \[ y^3 + \left(\frac{\pi^3}{8} - \frac{3\pi^2}{4}y + \frac{3\pi}{2}y^2 - y^3\right) = a \pi^3 \] This simplifies to: \[ \frac{\pi^3}{8} + \frac{3\pi}{2}y^2 - \frac{3\pi^2}{4}y = a \pi^3 \] ### Step 5: Rearrange the equation Rearranging gives: \[ \frac{3\pi}{2}y^2 - \frac{3\pi^2}{4}y + \left(\frac{\pi^3}{8} - a \pi^3\right) = 0 \] ### Step 6: Analyze the quadratic equation This is a quadratic equation in \( y \). For this equation to have real solutions, the discriminant must be non-negative: \[ D = \left(-\frac{3\pi^2}{4}\right)^2 - 4 \cdot \frac{3\pi}{2} \cdot \left(\frac{\pi^3}{8} - a \pi^3\right) \geq 0 \] ### Step 7: Calculate the discriminant Calculating the discriminant: \[ D = \frac{9\pi^4}{16} - 6\pi\left(\frac{\pi^3}{8} - a \pi^3\right) \] This simplifies to: \[ D = \frac{9\pi^4}{16} - \frac{3\pi^4}{4} + 6a\pi^4 \] Combining terms gives: \[ D = \left(6a - \frac{3}{4} + \frac{9}{16}\right)\pi^4 \] ### Step 8: Set the discriminant to be non-negative For \( D \geq 0 \): \[ 6a - \frac{3}{4} + \frac{9}{16} \geq 0 \] Solving this gives: \[ 6a \geq \frac{3}{4} - \frac{9}{16} \] Calculating the right-hand side: \[ \frac{3}{4} = \frac{12}{16} \Rightarrow \frac{12}{16} - \frac{9}{16} = \frac{3}{16} \] Thus: \[ 6a \geq \frac{3}{16} \Rightarrow a \geq \frac{1}{32} \] ### Conclusion for Statement I Thus, Statement I is correct for \( a > \frac{1}{32} \). ### Step 9: Analyze Statement II The statement is: \[ \sin^{-1} x + \cos^{-1} x = \frac{\pi}{2} \] This is always true for \( x \in [-1, 1] \). ### Step 10: Analyze the second part of Statement II We need to check: \[ 0 < \left(\sin x - \frac{\pi}{4}\right)^2 < \frac{9\pi^2}{16} \] This implies: \[ \sin x \neq \frac{\pi}{4} \] and the maximum value of \( \sin x \) is \( 1 \) when \( x = \frac{\pi}{2} \). ### Conclusion for Statement II Thus, Statement II is also correct. ### Final Conclusion Both Statement I and Statement II are correct.
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DISHA PUBLICATION-INVERSE TRIGONOMETIC FUNCTIONS-EXERCISE - 2: (CONCEPT APPLICATOR)
  1. Statement I: The equation ("sin"^-1x)^3 +("cos"^-1x)^3 -api^(3)=0 has ...

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  3. Find the domain and range of f(x) = sin^-1 (log [x]) + log (sin^-1 [x...

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  4. If sin^(-1)x+sin^(-1)y+sin^(-1)z=(3pi)/(2)p then the value of x^(100)+...

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  5. If u=cot^-1 sqrt(tanalpha)-tan^-1 sqrt(tan alpha), then tan(pi/4-u/2) ...

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  6. Find the real solutions of the eqution tan^(-1)sqrt(x(x+1))+sin^(-1)sq...

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  7. The domain set of the function f(x) = tan^(-1) x -cot ^(-1) x + cos ...

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  8. The sum of the infinite series "sin"^(-1)((1)/(sqrt2))+"sin"^(-1)((s...

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  9. If cos^(-1)x-"cos"^(-1)y/2=alpha, then 4x^(2)-4xycos alpha+y^(2) is eq...

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  10. 5cos^(-1)((1-x^(2))/(1+x^(2)))+7sin^(-1)((2x)/(1+x^(2)))-4tan^(-1)((2x...

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  11. If alpha="sin"^(-1)("cos"("sin"^(-1)x)) and beta="cos"^(-1)("sin"("cos...

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  12. If x, y, z are in A.P. and tan^(-1) x, tan^(-1) y and tan^(-1)z are al...

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  13. If cos^(-1)x+cos^(-1)y+cos^(-1)z=pi, then

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  14. Q. the value of tan^-1(a/(b+c))+tan^-1(b/(c+a)), if /=90^@ in triangle...

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  15. If 1/2"sin"^(-1)(2x)/(1+x^2)+1/2"cos"^(-1)(1-y^2)/(1+y^2)+1/3"tan"^(-1...

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  16. If cos^(-1)sqrt(p)+cos^(-1)sqrt(1-p)+cos^(-1)sqrt(1-q)=(3pi)/(4)"than ...

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  17. If A="tan"^(-1)((xsqrt3)/(2K-x)) and B="tan"^(-1)((2x-K)/(Ksqrt3)), th...

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  18. If f(x)=cot^(-1) ((3x-x^3)/(1-3x^2)) and g(x)=cos^(-1)((1-x^2)/(1+x^2)...

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  19. Find x satisfying [tan^(-1)x]+[cos^(-1)x]=2, where [] represents the g...

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  20. Evaluate underset(xto-1^(+))lim(sqrt(pi)-sqrt(cos^(-1)x))/(sqrt(1+x)).

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  21. The value of sin^(-1){cot(sin^(-1)(sqrt((2-sqrt3)/4)+cos^(-1)(sqrt(12)...

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