Hey guys. I'm a 2014 graduate. Post any questions and I'll do my best to help! (1 Viewer)

fifibum

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Hey, I'm doing prelim 3U trig and I don't know how to do this question from Maths In Focus:
Find the exact value of
2tan 120/1-tan^2 120

:/
 

Flop21

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Hey, I'm doing prelim 3U trig and I don't know how to do this question from Maths In Focus:
Find the exact value of
2tan 120/1-tan^2 120

:/
Is the answer -root(3)?
 

InteGrand

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Another way to do it is to recall that 2t/(1 – t2) = tan(theta), where t = tan(theta/2). In this case, theta/2 = 120 deg, so theta = 240 deg, so the expression equals tan(240 deg) = tan(60 deg) = sqrt(3).
 

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