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Determine tg [pi/2 - arctg(1/2)] .

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demadcrazy | Student, Grade 10 | (Level 1) Honors

Posted June 15, 2010 at 9:53 PM via web

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Determine tg [pi/2 - arctg(1/2)] .

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giorgiana1976 | College Teacher | (Level 3) Valedictorian

Posted June 15, 2010 at 9:54 PM (Answer #1)

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We'll use the formula tg(pi/2 - k) = ctg k.

Now, we'll apply the formula, where k = arctg(1/2)

tg[pi/2 - arctg(1/2)] = ctg [arctg(1/2)]

But ctg k = 1/tg k

ctg [arctg(1/2)]=1/tg(arctg(1/2))=1/(1/2)=2

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hala718 | High School Teacher | (Level 1) Educator Emeritus

Posted June 16, 2010 at 12:47 AM (Answer #2)

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tg(pi/2 -arctg(1/2)

We know that :

ctg (x)= tg(pi/2 - x)

==> tg(pi/2 -arctg(1/2)= ctg (arctg(1/2)

                               = ctg(arc ctg (2)

                              = 2

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neela | High School Teacher | (Level 3) Valedictorian

Posted June 16, 2010 at 12:57 AM (Answer #3)

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To detrmine  tg {pi/2 - arctg (1/2)}

Solution:

We know that tan (pi-x) = 1/tanx

So tan {pi/2-arctan (1/2)} = 1/ tan {arc tan(1/2)}

= 1/tan (1/2)

= 1/tan (0.5radians)

= 1/tan (28.64789 deg)

= 1.83049 nearly

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