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The general solution of the equation "...

The general solution of the equation
`"sin" 2x+ 2 "sin" x+ 2 "cos" x + 1 = 0`is

A

`3n pi - (pi)/(4), n in Z`

B

`2n pi + (pi)/(4), n in Z`

C

`2 n pi + (-1)^(n) "sin"^(-1) ((1)/(sqrt(3))), n in Z`

D

`n pi - (pi)/(4), n in Z`

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The correct Answer is:
To solve the equation \( \sin 2x + 2 \sin x + 2 \cos x + 1 = 0 \), we will follow these steps: ### Step 1: Rewrite the equation We start by rewriting the equation: \[ \sin 2x + 2 \sin x + 2 \cos x + 1 = 0 \] We know that \( \sin 2x = 2 \sin x \cos x \), so we can substitute this into the equation: \[ 2 \sin x \cos x + 2 \sin x + 2 \cos x + 1 = 0 \] ### Step 2: Factor out common terms Now, we can factor out 2 from the first three terms: \[ 2 (\sin x \cos x + \sin x + \cos x) + 1 = 0 \] This simplifies to: \[ 2 (\sin x \cos x + \sin x + \cos x) = -1 \] ### Step 3: Rearrange the equation Rearranging gives us: \[ \sin x \cos x + \sin x + \cos x = -\frac{1}{2} \] ### Step 4: Use trigonometric identities Next, we can express \( \sin x + \cos x \) in a more manageable form. We know: \[ \sin x + \cos x = \sqrt{2} \sin \left( x + \frac{\pi}{4} \right) \] Thus, we can rewrite the equation as: \[ \sqrt{2} \sin \left( x + \frac{\pi}{4} \right) + \sin x \cos x = -\frac{1}{2} \] ### Step 5: Substitute and simplify Now we can express \( \sin x \cos x \) as: \[ \sin x \cos x = \frac{1}{2} \sin 2x \] Substituting this back into the equation gives us: \[ \sqrt{2} \sin \left( x + \frac{\pi}{4} \right) + \frac{1}{2} \sin 2x = -\frac{1}{2} \] ### Step 6: Solve for \( \sin x + \cos x \) We can now set up the equation: \[ \sin x + \cos x = 0 \] This implies: \[ \sin x = -\cos x \] Dividing both sides by \( \cos x \) (assuming \( \cos x \neq 0 \)): \[ \tan x = -1 \] ### Step 7: General solution The general solution for \( \tan x = -1 \) is: \[ x = n\pi - \frac{\pi}{4}, \quad n \in \mathbb{Z} \] ### Final Answer Thus, the general solution of the equation \( \sin 2x + 2 \sin x + 2 \cos x + 1 = 0 \) is: \[ x = n\pi - \frac{\pi}{4}, \quad n \in \mathbb{Z} \] ---

To solve the equation \( \sin 2x + 2 \sin x + 2 \cos x + 1 = 0 \), we will follow these steps: ### Step 1: Rewrite the equation We start by rewriting the equation: \[ \sin 2x + 2 \sin x + 2 \cos x + 1 = 0 \] We know that \( \sin 2x = 2 \sin x \cos x \), so we can substitute this into the equation: ...
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OBJECTIVE RD SHARMA-TRIGONOMETRIC EQUATIONS AND INEQUATIONS-Chapter Test
  1. The general solution of the equation "sin" 2x+ 2 "sin" x+ 2 "cos" x...

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  2. If |k|=5 and 0^(@) le theta le 360^(@) , then the number of different...

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  3. The number of all the possible triplets (a1,a2,a3) such that a1+a2cos(...

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  4. The number of all possible 5-tuples (a(1),a(2),a(3),a(4),a(5)) such th...

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  5. The general solution of the equation "cos" x"cos"6x = -1, is

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  6. The values of x satisfying the system of equation 2^("sin" x + "cos"...

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  7. The general solution of the equation "tan" 3x = "tan" 5x, is

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  8. The number of all possible ordered pairs (x, y) x, y in R satisfying t...

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  9. If the expression ([s in(x/2)+cos(x/2)-i t a n(x)])/([1+2is in(x/2)])...

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  10. If the equation "sec" theta + "cosec" theta =c has real roots between ...

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  11. If the equation "sec" theta + "cosec" theta =c has real roots between ...

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  12. If theta(1), theta(2), theta(3), theta(4) are roots of the equation "s...

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  13. If sin(pi cos theta) = cos(pi sin theta), then of the value cos(th...

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  14. If "tan" (pi "cos" theta) = "cot"(pi "sin" theta), then the value(s) ...

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  15. The general solution of "tan" ((pi)/(2)"sin" theta) ="cot"((pi)/(2)"co...

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  16. The most general value of theta which satisfy both the equation cos th...

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  17. The number of roots of the equation x +2"tan"x = (pi)/(2) in the inter...

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  18. If "sin" (pi "cot" theta) = "cos" (pi "tan" theta), "then cosec" 2 the...

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  19. The number of distinct roots of the equation A"sin"^(3) x + B"cos"^(3...

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  20. The values of x between 0 and 2pi which satisfy the equation sinxsqrt(...

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  21. If Cos20^0=k and Cosx=2k^2-1, then the possible values of x between 0^...

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