Question

127,128,129. Решить.

Answer 1

$127)\; \; arccos\, 0,2164\approx 86,1137^\circ \; \; ;\; \; arccos\, 0,8771\approx 31,8950^\circ \; ;\\\\arccos\, 0,6081\approx 58,3864^\circ \; \; ;\; \; arccos\, 0,5666\approx 61,6517^\circ \; .\\\\128)\; \; arctg\, 0=0\; ,\; \; arctg(-1)=-\frac{\pi }{4}\; ,\; \; arctg\sqrt3\, =\frac{\pi }{3}\; ,\\\\arctg\frac{1}{\sqrt3}=\frac{\pi }{6}\; ,\; \; arctg(-\frac{1}{\sqrt3})=-\frac{\pi }{6} \; .$

$129)\; \; arctg\, 0,3541\approx 21,6656^\circ \; ,\; \; arctg\, 2,300\approx 73,8905^\circ \; ,\\\\arctg\, (-5)=-arctg\, 5=-87,4334^\circ \; ,\; \; arctg\, 10\approx 93,6549^\circ \; .$