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Category: Trigonometry

cot-cot-pi-4-2-

Question Number 106387 by bemath last updated on 05/Aug/20 cotθ+cot(π4+θ)=2θ=? Answered by 1549442205PVT last updated on 05/Aug/20 cotθ+cot(π4+θ)=2$$\Leftrightarrow\frac{\mathrm{sin}\left(\mathrm{2}\theta+\frac{\pi}{\mathrm{4}}\right)}{\mathrm{sin}\theta\mathrm{sin}\left(\frac{\pi}{\mathrm{4}}+\theta\right)}=\mathrm{2}\Leftrightarrow\mathrm{sin}\left(\frac{\pi}{\mathrm{4}}+\mathrm{2}\theta\right)=\mathrm{2sin}\theta\mathrm{sin}\left(\frac{\pi}{\mathrm{4}}+\theta\right) \

arc-tan-x-1-x-1-arc-tan-x-1-x-arc-tan-7-for-x-real-number-

Question Number 106286 by bemath last updated on 04/Aug/20 arctan(x+1x1)+arctan(x1x)=arctan(7)forxrealnumber Answered by bobhans last updated on 04/Aug/20 arctan(x+1x1)+arctan(x1x)=arctan(7)$$\mathrm{tan}\:\left(\mathrm{arc}\:\mathrm{tan}\:\left(\frac{\mathrm{x}+\mathrm{1}}{\mathrm{x}−\mathrm{1}}\right)+\mathrm{arc}\:\mathrm{tan}\:\left(\frac{\mathrm{x}−\mathrm{1}}{\mathrm{x}}\right)\right)=\mathrm{tan}\:\left(\mathrm{arc}\:\mathrm{tan}\:\left(−\mathrm{7}\right)\right) \