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If "sin "3theta = 4"sin" theta("sin"^(2)...

If `"sin "3theta = 4"sin" theta("sin"^(2) x-"sin"^(2)theta), theta ne npi, n in Z`. Then, the set of values of x, is

A

`{n pi +- (pi)/(3): n in Z}`

B

`{n pi +-(2pi)/(3): n in Z}`

C

`{n pi +- (pi)/(2): n in Z}`

D

`{n pi +- (pi)/(4): n in Z}`

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The correct Answer is:
To solve the equation \( \sin 3\theta = 4 \sin \theta (\sin^2 x - \sin^2 \theta) \), we will follow these steps: ### Step 1: Use the identity for \( \sin 3\theta \) We know that: \[ \sin 3\theta = 3 \sin \theta - 4 \sin^3 \theta \] Substituting this into the equation gives: \[ 3 \sin \theta - 4 \sin^3 \theta = 4 \sin \theta (\sin^2 x - \sin^2 \theta) \] ### Step 2: Expand the right-hand side Expanding the right-hand side: \[ 3 \sin \theta - 4 \sin^3 \theta = 4 \sin \theta \sin^2 x - 4 \sin \theta \sin^2 \theta \] ### Step 3: Rearranging the equation Now we can rearrange the equation: \[ 3 \sin \theta - 4 \sin \theta \sin^2 \theta = 4 \sin \theta \sin^2 x \] Factoring out \( \sin \theta \) (noting that \( \sin \theta \neq 0 \)): \[ \sin \theta (3 - 4 \sin^2 \theta) = 4 \sin \theta \sin^2 x \] ### Step 4: Cancel \( \sin \theta \) Since \( \sin \theta \neq 0 \), we can divide both sides by \( \sin \theta \): \[ 3 - 4 \sin^2 \theta = 4 \sin^2 x \] ### Step 5: Isolate \( \sin^2 x \) Rearranging gives: \[ 4 \sin^2 x = 3 - 4 \sin^2 \theta \] Thus, \[ \sin^2 x = \frac{3 - 4 \sin^2 \theta}{4} \] ### Step 6: Express \( \sin^2 x \) in terms of a known sine value We can rewrite \( \sin^2 x \): \[ \sin^2 x = \frac{3}{4} - \sin^2 \theta \] Recognizing that \( \frac{3}{4} = \left(\frac{\sqrt{3}}{2}\right)^2 \), we can express it as: \[ \sin^2 x = \left(\frac{\sqrt{3}}{2}\right)^2 - \sin^2 \theta \] ### Step 7: General solution for \( x \) Since \( \sin^2 x = \sin^2 \alpha \) where \( \alpha = \frac{\pi}{3} \), the general solution for \( x \) is: \[ x = n\pi \pm \frac{\pi}{3}, \quad n \in \mathbb{Z} \] ### Final Answer Thus, the set of values of \( x \) is: \[ x = n\pi + \frac{\pi}{3} \quad \text{or} \quad x = n\pi - \frac{\pi}{3}, \quad n \in \mathbb{Z} \]
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OBJECTIVE RD SHARMA ENGLISH-TRIGONOMETRIC EQUATIONS AND INEQUATIONS-Chapter Test
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  3. If rsintheta=3, r=4(1+sintheta) where 0<=theta<=2pi then theta e...

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  5. If the equation "sin" theta ("sin" theta + 2 "cos" theta) = a has a re...

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  6. The equation "sin"^(4) theta + "cos"^(4) theta = a has a real solution...

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  7. If 32"tan"^(8)theta" = 2"cos"^(2) alpha- 3"cos" alpha " and "3"cos" 2 ...

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  8. The general value of theta satisfying tantheta tan(120^@-theta) tan(12...

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  9. The solution of the equation "log"("cos"x) "sin" x + "log"("sin"x) "...

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  10. The number of solutions of the equation tanx+secx=2cosx lying in the i...

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  11. One root of the equation "cos" theta-theta + (1)/(2) = 0 lies in the i...

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  12. If "sin" (pi "cos" theta) = "cos" (pi "sin" theta), then which one fo ...

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  13. If "2sec" (2alpha) = "tan" beta + "cot"beta, then one of the value of ...

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  14. The values of k for which the equation sin^4 x+cos^4 x+sin2x+k=0 posse...

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  16. The number of solution of the equation |sin x|=|cos 3x| in [-2pi,2pi] ...

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  17. If sin x cos x cos 2x = lambda has a solution, then lambda lies in the...

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  18. If "sin "3theta = 4"sin" theta("sin"^(2) x-"sin"^(2)theta), theta ne n...

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  19. If sin 2x cos 2x cos 4x=lambda has a solution then lambda lies in the...

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  20. If the equation cos (lambda "sin" theta) = "sin" (lambda "cos" theta) ...

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