find the exact value of tan 112.50

Question

dumbcow · Answer

$$\tan 112.5 = \frac{\sin 122.5}{\cos 112.5} = \frac{\sin (90+\frac{45}{2})}{\cos (90+\frac{45}{2})} = \frac{\cos (\frac{45}{2})}{-\sin (\frac{45}{2})}$$
use half angle identity

anonymous · Answer

this is the whole equation?

dumbcow · Answer

look up the half angle identities for sin/cos

plug in values for sin(45/2) and cos(45/2)

simplify

anonymous · Answer

my answer is 2!!is this correct?

anonymous · Answer

hi

dumbcow · Answer

nope not quite http://www.wolframalpha.com/input/?i=tan%28112.5%29&a=TrigRD_D

anonymous · Answer

find the exact value of sin 112.5 also

dumbcow · Answer

what? well you are doing that in the process of getting tan(112.5)  lol

dumbcow · Answer

if you show your work i can assist in where you went wrong

dumbcow · Answer

http://en.wikipedia.org/wiki/Trig_Identity#Double-angle.2C_triple-angle.2C_and_half-angle_formulae