quick question (1 Viewer)

[gcmk]

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]

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

 

[gcmk]

ohh yeah thanks!