Math question

I have a friend, that saids, that sometimes angles in triangle may not sum up to 180 degrees. He also stated once, that there is a shape, that fit into square with finite area, but length of this shape is infinite. Not to mention, that he laughs hen I say, that x/x is always equal to 1. Is he trolling me or is he just a plain idiot?

>>5
No, it does not.
In fact, to prove that lim x->0 sin(x)/x is one, the series expansion at zero of sine: sin(x)= x + o(x), is used... which reduces the expression to lim x->0 x/x + o(x)/x; the first term is one, and the latter vanishes as per Landau Symbol definitions..