cos87°*cos432°-sin93°cos198°
=-cos93°*cos72°-sin93°*cos162°
=-cos93°*cos72°+sin93°*sin72°
=-cos(93+72)
=-cos165
=sin75
=sin(45+30)
=sin45*cos30+sin30*cos45
=(根号6+根号2)/4
cos87°*cos432°-sin93°cos198°
=-cos93°*cos72°-sin93°*cos162°
=-cos93°*cos72°+sin93°*sin72°
=-cos(93+72)
=-cos165
=sin75
=sin(45+30)
=sin45*cos30+sin30*cos45
=(根号6+根号2)/4