Question Number 183184 by Tawa11 last updated on 22/Dec/22
Commented by Tawa11 last updated on 22/Dec/22
$$\mathrm{Thanks}\:\mathrm{sir}.\:\mathrm{God}\:\mathrm{bless}\:\mathrm{you}. \\ $$
Answered by mr W last updated on 22/Dec/22
$${x}=\mathrm{tan}^{−\mathrm{1}} \left(\frac{\mathrm{tan}\:\mathrm{10}}{\mathrm{tan}\:\mathrm{20}\:\mathrm{tan}\:\mathrm{40}}\right)=\mathrm{30}° \\ $$
Commented by mr W last updated on 22/Dec/22
Commented by mr W last updated on 22/Dec/22
$$\mathrm{tan}\:{x}=\frac{{BD}}{{BC}}=\frac{{a}\:\mathrm{tan}\:\mathrm{10}°}{{a}\:\mathrm{tan}\:\mathrm{20}°\:\mathrm{tan}\:\mathrm{40}°}=\frac{\mathrm{tan}\:\mathrm{10}°}{\mathrm{tan}\:\mathrm{20}°\:\mathrm{tan}\:\mathrm{40}°} \\ $$$$\Rightarrow{x}=\mathrm{tan}^{−\mathrm{1}} \left(\frac{\mathrm{tan}\:\mathrm{10}°}{\mathrm{tan}\:\mathrm{20}°\:\mathrm{tan}\:\mathrm{40}°}\right)=\mathrm{30}° \\ $$
Commented by Tawa11 last updated on 22/Dec/22
$$\mathrm{Wow},\:\mathrm{God}\:\mathrm{bless}\:\mathrm{you}\:\mathrm{sir}. \\ $$
Commented by Tawa11 last updated on 22/Dec/22
$$\mathrm{I}\:\mathrm{don}'\mathrm{t}\:\mathrm{know}\:\mathrm{how}. \\ $$$$\mathrm{BC}\:\:=\:\:\mathrm{a}\:\mathrm{tan}\:\mathrm{20}\:\mathrm{tan}\:\mathrm{40} \\ $$
Commented by manxsol last updated on 23/Dec/22
Commented by Tawa11 last updated on 23/Dec/22
$$\mathrm{Very}\:\mathrm{clear}\:\mathrm{now}.\:\mathrm{God}\:\mathrm{bless}\:\mathrm{you}\:\mathrm{sir}. \\ $$