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quick question (1 Viewer)

gcmk

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i'm confused about this question~~
i want to know if im doing the right thing so plz help =)

prove:
(cosU cotU- sinU tanU) sinU cosU / cos U- sinU= 1+sinU cosU


thanks!
 

onebytwo

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inner west
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gcmk said:
i'm confused about this question~~
i want to know if im doing the right thing so plz help =)

prove:
(cosU cotU- sinU tanU) sinU cosU / cos U- sinU= 1+sinU cosU


thanks!
change the cotU to cosU/sinU on the LHS and the tanU to sinU/cosU, then put the two fractions as one to get [(cos^3U-sin^3U)/sinUcosU]sinUcosU
thats a start..also use the expansion for the cubic and cancel
and remeber the cos^2U+sin^2U=1
 

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