Can someone explain to me why xcosx - sinx = 0 when x = tanx?

Thanks.

Printable View

- Nov 6th 2012, 07:35 AMalyosha2x = tanx
Can someone explain to me why xcosx - sinx = 0 when x = tanx?

Thanks. - Nov 6th 2012, 09:38 AMebainesRe: x = tanx
Replace tanx with sinx/cosx and it comes right out.

- Nov 6th 2012, 06:27 PMtopsquarkRe: x = tanx
Asked and answered in the other thread.

Please do not double post.

-Dan - Apr 6th 2013, 08:39 PMmathguy25Re: x = tanx
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

= 0