Question

Trig help!

Answer 1

#12 please!

Answer 2

Here are a couple hints:

1. \(\cot x = \dfrac{1}{\tan x}\).
2. \(\tan x\) is \(\pi\)-periodic, i.e. \(\tan(x+\pi) = \tan x\).

Can you use these hints to answer your problem?

Answer 3

no i can't

Answer 4

i mean it works for part B but how about for part A?

Answer 5

\[\frac{4}{9}=\frac{1}{18}+\frac{7}{18}\] i am stumped

Answer 6

i was thinking a cofunction identity
but i dont see the connection
part B is ok because of what @ChristopherToni said above

Answer 7

hm not sure

Answer 8

maybe i am just old an tired
@ChristopherToni you got the solution ?

Answer 9

I'm trying to think of different things that would work. I'm testing out the idea of using the identity \(\cot(\theta/2) = \csc\theta+\cot\theta\) somehow. I'll post back if I make progress.

Answer 10

okay thank you

Answer 11

This is stupid. \(\dfrac{\pi}{18} = \dfrac{\pi}{2}-\dfrac{4\pi}{9}\)

Furthermore, recalling that \(\cot\left(\dfrac{\pi}{2}-x\right) = \tan x\), we now can conclude that \(\cot\left(\dfrac{\pi}{18}\right) = \tan\left(\dfrac{4\pi}{9}\right).\)