1. anonymous

Evaluate the expression using an appropriate double angle formula. 6tan(75) / 1-tan^2(75)

2. precal

can you use a calculator or not?

3. anonymous

i have to show the working

4. anonymous

please could you show me how to do it ?

5. Mertsj

$\tan 2A=\frac{2\tan A}{1-\tan ^{2}A}$

6. Mertsj

$\frac{6\tan 75}{1-\tan ^{2}75}=\frac{(3)2\tan 75}{1-\tan ^{2}75}=3\tan 2A$

7. Mertsj

$2A=150, \tan(150)=-\frac{\sqrt{3}}{3}$

8. Mertsj

$3\tan 2A=3(-\frac{\sqrt{3}}{3} )= -\sqrt{3}$