# tangent cone to the set

I'm supposed to solve this problem:

Let us consider the set $M=\{(x, \sin{x}):x\in\mathbb{R}\}\cup\{\big(\cos(x)-1,x\big):x\in\mathbb{R}\}$

The question is to find the tangent cone to the set $M$ in point $(0,0)$

I would appreciate any help. I have no clue how to solve this problem and need to find the solution to move further.

• Did you try sketching a graph of that set? The answer should be obvious from the picture. – Daniel McLaury May 13 '15 at 1:59