1. The problem statement, all variables and given/known data prove lim h-->0 sin(h)/h = 1 2. Relevant equations I understand the idea of squeze theorom. Understand that area of small triangle < sector area< big triangle. I know 1/2sin(h) < 1/2h < 1/2(sin(h)/cos(h)). In my calc book it goes from sinh< h< (sinh/cosh) to cos(h)/sin(h)< 1/h <1/sin(h). How does this happen? 3. The attempt at a solution multiply outside by cos(h) but inside is just reciprocal.