cos5π/6=-cosπ/6=-根号3/2
arccosx=5π/6
X=-根号3/2
arctan(2x/3)
=arctan(-根号3/2*2/3)
=arctan(-根号3/3)
tan5π/6=-根号3/3
arctan(2x/3)=5π/6
cos5π/6=-cosπ/6=-根号3/2
arccosx=5π/6
X=-根号3/2
arctan(2x/3)
=arctan(-根号3/2*2/3)
=arctan(-根号3/3)
tan5π/6=-根号3/3
arctan(2x/3)=5π/6