I NEED HELP PROVING THIS IDENTITY.......prove identity tan3Ѳ=3tanѲ-tan^3Ѳ/1-3tan^2Ѳ
to do .................(1)
recall that
thus, we can start with the left hand side of equation (1), and note that ..........................(2)
we can further break down using the same formula.
plug this into equation (2) and simplify to make it look like the right hand side of equation (1)
Okay, I wasn't right in the head when I chose to prove it from RHS. Here's my solution (I skipped some steps but you can follow up, lol):
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I skipped some steps where I switched into
I hope I didn't make a mistake or typo.
If you want another method out of the norm....
(I skipped a few steps, you should know this formula )
Factor by :
Use identity (we'll use it for the denominator) and (we'll use it for the numerator).
This yields :
Multiply by :
If you want to do it a complicated way, do it COMPLETELY !
(A few more steps could've been skipped but... it's better leaving them )
Edit : similar to Chops', but he used inverse trig functions (boooo) and I did it the reverse order LOL