As shown in fig. 3, point D moves on line segment OB (except endpoints O and B), and a straight line AB intersects with DE⊥CD at point E, that is, AB⊥x axis.
<As shown in fig. 3, point D moves on line segment OB (except endpoints O and B), and a straight line AB intersects with DE⊥CD at point E, that is, AB⊥x axis.
The bisector of ∠ bed and ∠DCO passes through point m, and the size of ∠M is found.