1. The problem statement, all variables and given/known data Find the limits of the following functions: a) lim x->0 x^2/(1-cos^2x) b) lim x->0 sin3x/sin5x c) lim x->pi/4 (tanx-1)/(x-(pi/4)) 2. Relevant equations All those special triginometric simplifying rules and the fundamental triginometric limit 3. The attempt at a solution For a) I simplified the denominator to sin^2x, but after that I got lost. The answer is 1, but I don't think x/sinx would equal 1 like sinx/x does. For b) I tried using the variable substitution method by making u=3x, but then I encounter problems with the denominator again as I do not have any idea how to simplify sin5(3/u). For c) it is much the same thing, beyond replacing tanx with sinx/cosx I do not know how to proceed with the simplification. Any help would be greatly appreciated, thanks.