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    ​If sin⁡θ+cos⁡θ=3cos⁡(90−θ) then tan⁡θ=?\text{If } \sin \theta + \cos \theta = \sqrt{3} \cos(90 - \theta) \text{ then } \tan \theta = ?
    Question

    If sinθ+cosθ=3cos(90θ) then tanθ=?\text{If } \sin \theta + \cos \theta = \sqrt{3} \cos(90 - \theta) \text{ then } \tan \theta = ?​​

    A.

    21\sqrt{2-1}​​

    B.

    131\frac{1}{\sqrt{3}-1}​​

    C.

    121\frac{1}{\sqrt{2}-1}​​

    D.

    31\sqrt{3}{-1}​​

    Correct option is B

    Given: 

    sinθ+cosθ=3cos(90θ)\sin\theta+\cos\theta = \sqrt3\cos( 90-\theta) 

    Solution:

    sinθ+cosθ=3cos(90θ)\sin\theta + \cos\theta = \sqrt3\cos(90^\circ - \theta)             (  cos(90θ)=sinθ\cos(90^\circ - \theta) = \sin\theta  )​

    sinθ+cosθ=3sinθ\sin\theta + \cos\theta = \sqrt3\sin\theta​​

    sinθsinθ+cosθsinθ=3\frac{\sin\theta}{\sin\theta} + \frac{\cos\theta}{\sin\theta} = \sqrt3   

    1+cosθsinθ=31 + \frac{\cos\theta}{\sin\theta} = \sqrt3 

    cosθsinθ=31 \frac{\cos\theta}{\sin\theta} = \sqrt3-1 

    sinθcosθ=131\frac{\sin\theta}{\cos\theta} = \frac1{\sqrt3-1} 

    tanθ=131\tan\theta = \frac1{\sqrt3-1}  

    Option (b)

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