Thread: How to calculate arctan(0) ? View Single Post
 P: 2,218 Arctan(x) = Pi means x = tan(pi) $$tan(\pi) = \frac{0up}{1left} = 0$$ Arctan(x) = 0 means x = tan(0) $$tan(0) = \frac{0up}{1right} = 0$$ Get it? 2. The answer is in limits. $$arctan(1/0) = undefined$$ However the limit is defined: $$\lim x\rightarrow 0 \mbox{ of } arctan(1/x) = \frac{\pi}{2}$$ Try graphing the function arctan(x) and use the trace tool to see the values at those points.