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The simplest form of tan⁡−11+x2−1x\tan^{-1} \frac{\sqrt{1+x^2} - 1}{x}, x≠0x \neq 0 is:

Solution

✅ Correct Option: 3

Let x=tan⁡θx = \tan\theta, so 1+x2=sec⁡θ\sqrt{1+x^2} = \sec\theta. Then (sec⁡θ−1)/tan⁡θ=(1−cos⁡θ)/sin⁡θ=tan⁡(θ/2)(\sec\theta - 1)/\tan\theta = (1 - \cos\theta)/\sin\theta = \tan(\theta/2). Hence tan⁡−1(tan⁡(θ/2))=θ/2=(1/2)tan⁡−1x\tan^{-1}(\tan(\theta/2)) = \theta/2 = (1/2)\tan^{-1}x.

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