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If sin^(-1)x+cos^(-1)(1-x)=sin^(-1)(-x),...

If `sin^(-1)x+cos^(-1)(1-x)=sin^(-1)(-x)`, then x satisfies the equation

A

`2x^(2)-x+2=0`

B

`2x^(2)-3x=0`

C

`2x^(2)+x-1=0`

D

None of these

Text Solution

AI Generated Solution

The correct Answer is:
To solve the equation \( \sin^{-1} x + \cos^{-1} (1 - x) = \sin^{-1} (-x) \), we will follow these steps: ### Step 1: Rewrite the Equation We start with the given equation: \[ \sin^{-1} x + \cos^{-1} (1 - x) = \sin^{-1} (-x) \] ### Step 2: Use the Identity for \(\cos^{-1}\) Recall that: \[ \cos^{-1} y = \frac{\pi}{2} - \sin^{-1} y \] Using this identity, we can rewrite \(\cos^{-1} (1 - x)\): \[ \cos^{-1} (1 - x) = \frac{\pi}{2} - \sin^{-1} (1 - x) \] ### Step 3: Substitute Back into the Equation Substituting this into the original equation gives: \[ \sin^{-1} x + \left( \frac{\pi}{2} - \sin^{-1} (1 - x) \right) = \sin^{-1} (-x) \] This simplifies to: \[ \sin^{-1} x + \frac{\pi}{2} - \sin^{-1} (1 - x) = \sin^{-1} (-x) \] ### Step 4: Rearranging the Equation Rearranging the equation, we have: \[ \sin^{-1} x - \sin^{-1} (1 - x) = \sin^{-1} (-x) - \frac{\pi}{2} \] ### Step 5: Use the Identity for \(\sin^{-1} (-x)\) We know that: \[ \sin^{-1} (-x) = -\sin^{-1} x \] Substituting this into our equation gives: \[ \sin^{-1} x - \sin^{-1} (1 - x) = -\sin^{-1} x - \frac{\pi}{2} \] ### Step 6: Combine Like Terms Combining like terms results in: \[ 2\sin^{-1} x = -\sin^{-1} (1 - x) - \frac{\pi}{2} \] ### Step 7: Solve for \(x\) To solve for \(x\), we can express \(\sin^{-1} (1 - x)\) in terms of \(x\): \[ \sin^{-1} (1 - x) = \frac{\pi}{2} + 2\sin^{-1} x \] This leads us to: \[ 1 - x = \sin\left(\frac{\pi}{2} + 2\sin^{-1} x\right) \] Using the sine addition formula, we can simplify this further. ### Step 8: Find Values of \(x\) After solving the equation, we find two potential solutions: 1. \(x = 0\) 2. \(x = \frac{1}{2}\) ### Step 9: Verify the Solutions We substitute \(x = 0\) and \(x = \frac{1}{2}\) back into the original equation to check which one satisfies it: - For \(x = 0\): \[ \sin^{-1}(0) + \cos^{-1}(1) = \sin^{-1}(0) \quad \Rightarrow \quad 0 + 0 = 0 \quad \text{(True)} \] - For \(x = \frac{1}{2}\): \[ \sin^{-1}\left(\frac{1}{2}\right) + \cos^{-1}\left(\frac{1}{2}\right) = \sin^{-1}\left(-\frac{1}{2}\right) \quad \Rightarrow \quad \frac{\pi}{6} + \frac{\pi}{3} \neq -\frac{\pi}{6} \quad \text{(False)} \] Thus, the only solution that satisfies the equation is: \[ \boxed{0} \]
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