\operatorname{arccos} (x) = \frac{\pi}{2} - x - \frac{1}{6} x^{3} - \frac{3}{40} x^{5} - \frac{5}{112} x^{7} - \frac{35}{1152} x^{9} - \frac{63}{2816} x^{11} - \frac{231}{13312} \\ \quad{}\quad{}x^{13} - \frac{143}{10240} x^{15} + \operatorname{O} \bigl(x^{16}\bigr)

`&operatorname`(arccos)(x) = series(1/2*Pi-1*x-1/6*x^3-3/40*x^5-5/112*x^7-35/1152*x^9-63/2816*x^11-231/13312*x^13-143/10240*x^15+O(x^16),x,16)