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March 29th, 2010, 08:18 AM   #1
Joined: Mar 2010

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Trig simplification

Hi guys, I've got a math issue regrding trig... I need to show that

tan (4 arctan(1/5)) = 120/119

for a proof I'm doing. How would I go about doing/simplifying this?

Uss_Defiant is offline  
March 29th, 2010, 10:10 AM   #2
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From: Adelaide, Australia

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Re: Trig simplification

Hi there; just use the identity twice.

That is, find tan 2x assuming you know that tan x = 1/5, then use that to find tan (2(2x)).
aswoods is offline  

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