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Question Number 28624 by Joel578 last updated on 28/Jan/18

Commented by Joel578 last updated on 28/Jan/18

Find the value of  the given expression

$$\mathrm{Find}\:\mathrm{the}\:\mathrm{value}\:\mathrm{of}\:\:\mathrm{the}\:\mathrm{given}\:\mathrm{expression} \\ $$

Commented by Tinkutara last updated on 28/Jan/18

1?

Commented by matikzone.tk last updated on 28/Jan/18

piye kabare pak joel?

$${piye}\:{kabare}\:{pak}\:{joel}? \\ $$

Commented by Joel578 last updated on 29/Jan/18

baik

$${baik} \\ $$

Answered by moxhix last updated on 28/Jan/18

show: if  0<α,β,γ<π, α+β+γ=π  then tanα+tanβ+tanγ=tanαtanβtanγ .  //  tanα=−tan(π−α)=−tan(β+γ)      =−((tanβ+tanγ)/(1−tanβtanγ))  tanα(1−tanβtanγ)=−tanβ−tanγ  ∴ tanα+tanβ+tanγ=tanαtanβtanγ .  (∴((tanα+tanβ+tanγ)/(tanαtanβtanγ))=1)  //  now we set α=((2π)/(2017)), β=((1006π)/(2017)), γ=((1009π)/(2017)) .

$$\mathrm{show}:\:\mathrm{if}\:\:\mathrm{0}<\alpha,\beta,\gamma<\pi,\:\alpha+\beta+\gamma=\pi \\ $$$$\mathrm{then}\:{tan}\alpha+{tan}\beta+{tan}\gamma={tan}\alpha{tan}\beta{tan}\gamma\:. \\ $$$$// \\ $$$${tan}\alpha=−{tan}\left(\pi−\alpha\right)=−{tan}\left(\beta+\gamma\right) \\ $$$$\:\:\:\:=−\frac{{tan}\beta+{tan}\gamma}{\mathrm{1}−{tan}\beta{tan}\gamma} \\ $$$${tan}\alpha\left(\mathrm{1}−{tan}\beta{tan}\gamma\right)=−{tan}\beta−{tan}\gamma \\ $$$$\therefore\:{tan}\alpha+{tan}\beta+{tan}\gamma={tan}\alpha{tan}\beta{tan}\gamma\:. \\ $$$$\left(\therefore\frac{{tan}\alpha+{tan}\beta+{tan}\gamma}{{tan}\alpha{tan}\beta{tan}\gamma}=\mathrm{1}\right) \\ $$$$// \\ $$$$\mathrm{now}\:\mathrm{we}\:\mathrm{set}\:\alpha=\frac{\mathrm{2}\pi}{\mathrm{2017}},\:\beta=\frac{\mathrm{1006}\pi}{\mathrm{2017}},\:\gamma=\frac{\mathrm{1009}\pi}{\mathrm{2017}}\:. \\ $$

Commented by Joel578 last updated on 29/Jan/18

thank you very much

$${thank}\:{you}\:{very}\:{much} \\ $$

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