sin^2 x + cos 2x = cos^2 x
2 / cot x - tan x = tan 2x
2007-01-04 02:00:31 · 3 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics
Yes...prove them....
2007-01-04 02:33:29 · update #1
sin^2 x + cos 2x = cos^2 x
sin^2 x +cos^2 x -sin^2 x =cos^2 x
cos^2 x = cos^2x
2 / cot x - tan x = tan 2x
2tan x-tan x = tan 2x
tan x = tan 2x
The above is not true so original expression is not an identity
2007-01-04 02:16:22 · answer #1 · answered by ironduke8159 7 · 0⤊ 0⤋
are you supposed to be proving these identities?
for the first one, you can derive this equation from the sum identity:
cos (A + B) = cos A cos B - sin A sin B
for the second one, apply the sum identity for tangent:
tan 2x = (2 tan x) / 1 - tan^2 x
2007-01-04 02:08:38 · answer #2 · answered by january 2 · 0⤊ 0⤋
First One is TRUE
Second One is ???
2007-01-04 02:13:03 · answer #3 · answered by GTA 2 · 0⤊ 0⤋