trigonometric problem
Asked by
30th August 2008,
4:50 PM
Answered by Expert
Answer:
we know that tanx = 2 tan x/2 / (1-tan2 x/2)
also cos2x = cos2x-sin2x = (cos2x-sin2x) / (cos2x+sin2x) = (1-tan2x) / (1+tan2x)
so 1+ tanx tan x/2 = 1 + 2tan2 x/2 / (1-tan2 x/2) = (1+tan2x/2) / (1-tan2x/2) = 1/cos x = sec x
similarly tanx cot x/2 -1 = -1 + 2 / (1-tan2 x/2) = (1+tan2x/2) / (1-tan2x/2) = 1/cos x = sec x
Answered by Expert
12th September 2008,
3:48 AM
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