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If 1+sin⁡2θ=3sin⁡θcos⁡θ1 + \sin^2\theta = 3 \sin \theta \cos \theta, then tan⁡θ\tan \theta can take values

Solution

✅ Correct Option: 1

Given: 1+sin⁡2θ=3sin⁡θcos⁡θ1 + \sin^2\theta = 3 \sin \theta \cos \theta

sin⁡2θ+cos⁡2θ=1\sin^2\theta + \cos^2\theta = 1

sin⁡2θ=1−cos⁡2θ\sin^2\theta = 1 - \cos^2\theta


1+(1−cos⁡2θ)=3sin⁡θcos⁡θ1 + (1 - \cos^2\theta) = 3 \sin \theta \cos \theta

2−cos⁡2θ=3sin⁡θcos⁡θ2 - \cos^2\theta = 3 \sin \theta \cos \theta


2−cos⁡2θcos⁡2θ=3sin⁡θcos⁡θcos⁡2θ\dfrac{2 - \cos^2\theta}{\cos^2\theta} = \dfrac{3 \sin \theta \cos \theta}{\cos^2\theta}

2cos⁡2θ−1=3⋅sin⁡θcos⁡θ\dfrac{2}{\cos^2\theta} - 1 = 3 \cdot \dfrac{\sin\theta}{\cos\theta}


1cos⁡2θ=1+tan⁡2θ\dfrac{1}{\cos^2\theta} = 1 + \tan^2\theta and sin⁡θcos⁡θ=tan⁡θ\dfrac{\sin\theta}{\cos\theta} = \tan\theta

2(1+tan⁡2θ)−1=3tan⁡θ2(1 + \tan^2\theta) - 1 = 3\tan\theta

2+2tan⁡2θ−1=3tan⁡θ2 + 2\tan^2\theta - 1 = 3\tan\theta

1+2tan⁡2θ=3tan⁡θ1 + 2\tan^2\theta = 3\tan\theta


2tan⁡2θ−3tan⁡θ+1=02\tan^2\theta - 3\tan\theta + 1 = 0

t=tan⁡θt = \tan\theta

2t2−3t+1=02t^2 - 3t + 1 = 0


t=3±9−84t = \dfrac{3 \pm \sqrt{9 - 8}}{4}

t=3±14t = \dfrac{3 \pm 1}{4}

t=44=1t = \dfrac{4}{4} = 1 or t=24=12t = \dfrac{2}{4} = \dfrac{1}{2}


Therefore, tan⁡θ\tan \theta can take the values 12\dfrac{1}{2} and 11.

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