So sánh góc BAM và góc CAM

$$\begin{gathered} \mathrm{Cho} ∆\mathrm{ABC} \mathrm{có} \stackrel{⏜}{\mathrm{B}}>\stackrel{⏜}{\mathrm{C}}. \mathrm{Gọi} \mathrm{M} \mathrm{là} \mathrm{trung} \mathrm{điểm} \mathrm{của} \mathrm{BC}. \mathrm{Trên} \mathrm{tia} \mathrm{đối} \mathrm{của} \mathrm{MA} \mathrm{lấy} \mathrm{E} \mathrm{sao} \mathrm{cho} \mathrm{ME}=\mathrm{MA}. \\ \mathrm{a}) \mathrm{So} \mathrm{sánh} \widehat{\mathrm{BAM}} \mathrm{và} \widehat{\mathrm{CAM}} \\ \mathrm{b}) \mathrm{So} \mathrm{sánh} \mathrm{hai} \mathrm{đoạn} \mathrm{thằng} \mathrm{AC} \mathrm{và} \mathrm{AM} \end{gathered}$$