nilai eksak dari tan 15 derajat adalah

[tex]
\tan{15\degree}\\
=\tan{(60\degree-45\degree)}\\
=\frac{\tan{60\degree}-\tan{45\degree}}{1+\tan{60\degree}\tan{45\degree}}\\
=\frac{\sqrt{3}-1}{1+\sqrt{3}\cdot1}\\
=\frac{\sqrt{3}-1}{\sqrt{3}+1}
[/tex]