(sin22度+cos45度*sin23度)/cos22度-sin45度*sin23度
=(sin22度+cos(22+23)度*sin23度)/cos22度-sin(22+23)度*sin23度
=(sin22度+cos22cos23sin23-sin22sin23^2)/cos22度-sin22cos23sin23-cos22sin23^2
=[sin22(1-sin23^2)+cos22cos23sin23]/[cos22(1-sin23^2)-sin22cos23sin23]
=(sin22cos23^2+cos22cos23sin23)/(cos22cos23^2-sin22sin23cos23)
=(sin22cos23+cos22sin23)/(cos22cos23-sin22sin23)
=sin(22+23)/cos(22+23)
=tg45
=1