Can someone explain to me why xcosx - sinx = 0 when x = tanx?
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Replace tanx with sinx/cosx and it comes right out.
Asked and answered in the other thread.
Please do not double post.
Last edited by topsquark; Nov 6th 2012 at 06:30 PM.
Let x = tan x. Then
x cos x - sin x
= tan x * cos x - sin x
= (sin x / cos x) * cos x - sin x
= sin x - sin x
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