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If a le 1/32 then the number of solution...

If `a le 1/32` then the number of solution of
`(sin^(-1) x)^(3) +(cos^(-1) x)^(3) = a pi^(3)` is

A

0

B

1

C

2

D

infinite

Text Solution

AI Generated Solution

The correct Answer is:
To solve the equation \((\sin^{-1} x)^3 + (\cos^{-1} x)^3 = a \pi^3\) under the condition \(a \leq \frac{1}{32}\), we will follow these steps: ### Step 1: Use the identity for the sum of cubes We know the identity for the sum of cubes: \[ A^3 + B^3 = (A + B)(A^2 - AB + B^2) \] Let \(A = \sin^{-1} x\) and \(B = \cos^{-1} x\). Then, we can rewrite the equation as: \[ (\sin^{-1} x + \cos^{-1} x)((\sin^{-1} x)^2 - \sin^{-1} x \cos^{-1} x + (\cos^{-1} x)^2) = a \pi^3 \] ### Step 2: Simplify using the known identity We know that: \[ \sin^{-1} x + \cos^{-1} x = \frac{\pi}{2} \] Substituting this into our equation gives: \[ \frac{\pi}{2} \left((\sin^{-1} x)^2 - \sin^{-1} x \cos^{-1} x + (\cos^{-1} x)^2\right) = a \pi^3 \] ### Step 3: Rearranging the equation This simplifies to: \[ \left((\sin^{-1} x)^2 - \sin^{-1} x \cos^{-1} x + (\cos^{-1} x)^2\right) = \frac{2a \pi^2}{\pi} = 2a \pi^2 \] ### Step 4: Express \((\sin^{-1} x)^2 + (\cos^{-1} x)^2\) Using the identity: \[ (\sin^{-1} x)^2 + (\cos^{-1} x)^2 = \left(\frac{\pi^2}{4}\right) - 2\sin^{-1} x \cos^{-1} x \] We can substitute this into our equation: \[ \frac{\pi^2}{4} - 2\sin^{-1} x \cos^{-1} x - \sin^{-1} x \cos^{-1} x = 2a \pi^2 \] This simplifies to: \[ \frac{\pi^2}{4} - 3\sin^{-1} x \cos^{-1} x = 2a \pi^2 \] ### Step 5: Rearranging for \(\sin^{-1} x \cos^{-1} x\) Rearranging gives: \[ 3\sin^{-1} x \cos^{-1} x = \frac{\pi^2}{4} - 2a \pi^2 \] Thus, \[ \sin^{-1} x \cos^{-1} x = \frac{\pi^2}{12} - \frac{2a \pi^2}{3} \] ### Step 6: Analyzing the range of \(\sin^{-1} x \cos^{-1} x\) The maximum value of \(\sin^{-1} x \cos^{-1} x\) occurs when \(x = \frac{1}{\sqrt{2}}\), giving: \[ \sin^{-1} \frac{1}{\sqrt{2}} \cos^{-1} \frac{1}{\sqrt{2}} = \frac{\pi}{4} \cdot \frac{\pi}{4} = \frac{\pi^2}{16} \] ### Step 7: Setting the inequality We need: \[ \frac{\pi^2}{12} - \frac{2a \pi^2}{3} \leq \frac{\pi^2}{16} \] This leads to: \[ \frac{1}{12} - \frac{2a}{3} \leq \frac{1}{16} \] Solving this inequality will give us the possible values for \(a\). ### Step 8: Solve for \(a\) Multiplying through by \(48\) (the least common multiple of 12 and 16): \[ 4 - 32a \leq 3 \] This simplifies to: \[ 1 \leq 32a \implies a \geq \frac{1}{32} \] ### Conclusion Since \(a \leq \frac{1}{32}\) and \(a \geq \frac{1}{32}\), we conclude that \(a = \frac{1}{32}\). This means the equation has no solutions because the maximum value of \(\sin^{-1} x \cos^{-1} x\) cannot reach the required value for any \(x\) in the domain. ### Final Answer Thus, the number of solutions is **0**. ---
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OBJECTIVE RD SHARMA ENGLISH-INVERSE TRIGONOMETRIC FUNCTIONS -Exercise
  1. Find the smallest and the largest values of tan^(-1) ((1 - x)/(1 + x))...

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  2. The least and the greatest values of (sin^(-1)x)^3+(cos^(-1)x)^3 are (...

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  3. If a le 1/32 then the number of solution of (sin^(-1) x)^(3) +(cos^(...

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  4. If x takes negative permissible value then sin^(-1)x=

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  5. If -1 le x le -(1)/sqrt(2) then sin^(-1)2xsqrt(1-x^(2)) equals

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  6. If (1)/sqrt(2) le x le 1 then sin^(-1) 2xsqrt(1-x^(2)) equals

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  7. If 0 le x le 1 then cos^(-1)(2x^(2)-1) equals

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  8. If -1 le x le 0 then cos^(-1)(2x^(2)-1) equals

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  9. If -1/2 le x le 1/2 then sin^(-1)3x-4x^(3) equals

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  10. If 1/2 le x le 1 then sin^(-1)3x-4x^(3) equals

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  11. If -1 le x le -1/2, then sin^(-1)(3x-4x^3) equals

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  12. If 1/2 le x le 1 then cos^(-1)(4x^(3)-3x) equals

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  13. if -1/2 le x le 1/2 then cos^(-1)(4x^(3)-3x) equals

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  14. if -1 le x le -1/2 then cos^(-1)(4x^(3)-3x) equals

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  15. If 0 lt x lt 1 then tan^(-1) (2x)/(1-x^(2)) equals

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  16. If x in (1,oo) then tan^(-1)((2x)/(1-x^(2))) equals

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  17. if x in (-oo,-1) then tan^(-1)(2x)/(1-x^(2)) equals

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  18. Prove that 3 tan^(-1) x= {(tan^(-1) ((3x - x^(3))/(1 - 3x^(2))),"if ...

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  19. Prove that 3 tan^(-1) x= {(tan^(-1) ((3x - x^(3))/(1 - 3x^(2))),"if ...

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  20. Prove that 3 tan^(-1) x= {(tan^(-1) ((3x - x^(3))/(1 - 3x^(2))),"if ...

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