Question

$\log (\tan 18°)+\log (\tan 36°)+\log (\tan 54°)+\log (\tan 72°)=$

• A. $\log 4$
• B. $\log 3$
• C. $\log 2$
• D. 0

Answer 1

Answer: (D)

$\log (\tan 18°\tan 36°\tan 54°\tan 72°)=\log 1$
$[\because IfA+B=90^{\circ }\Rightarrow \tan A\tan B=1]$