(tan^2 X+tanX+1)(cot^2 X -cot+1)=tan^2 X+cot^2 x+1
HELP
thz
A MATHS,,,HELP
2007-11-13 4:05 am
回答 (1)
2007-11-13 4:19 am
✔ 最佳答案
Is it an identity to prove? If so, L.H.S. = ( tan^2 x + tan x + 1 )( cot^2 x - cot x + 1 )
= 1 - tanx + tan^2 x + cot x - 1 + tanx + cot^2 x - cot x + 1
= 2 + tan^2 x + cot^2x - 1
= tan^2 x + cot^2 x + 1
= R.H.S.
參考: My Maths Knowledge
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