I'm lost, can someone tell me how to do this?
I got to
cosx/(sinx/cosx) = cosx*(cosx/sinx) = cos^2x/sinx = 1-sin^2x/sinx ???
>>39820
Dude, that's bait. It's not an equality.
=> cos*sin = (1-cos)(sin/cos)
=> cos = (1-cos)/cos
=> cos^2 =(1-cos)
so it is only true for all x if (1-cos) had been (1-sin^2)
unless you want to solve it for a specific x value
>>39837
which has solution x = 0.904
>>39833
>>39826
The question asked for which of the 4 isn't an identity, and the textbook answer is b.
So either this is an identity or the textbook went full retard like 1/3 of the time.
>>39850
>facepalm.jpg
The left side should be [ (1 - cos x) / cos x ] / tan x . That top line belongs to d, not c.
>>39861
well shit
>>39861
then it's actually easy to see:
multiply by (sin x tan x)/(1-cos x) and you obtain:
sin x / cos x = tan x
>>39937
i think the issue here was he read the problem wrong. its pretty obvious how b. isnt an identity and the rest are.
