運算式 2: StartFraction, 1 Over sin left parenthesis, "x" , right parenthesis , EndFraction minus StartFraction, 1 Over cos left parenthesis, 2 "x" , right parenthesis cos left parenthesis, 3 "x" , right parenthesis , EndFraction left brace, 0 less than or equal to "x" less than or equal to 2 pi , right brace1sinx−1cos2xcos3x0≤x≤2π