I have always taken for granted sin, cos, and tan... but now i want to try to understand something about the unit circle which i have neglected through high school... lol. Well, I have a statement that says sin x < x < tan x. Can someone please bring me through why this is the case geometrically. Also, i am able to prove lim(x->0) sin(x)/(x) = 1 from this but just wondering what the proof for lim(x->0) sin(kx)/(x) = k looks like.