下列表达式中( )首先进行的运算是 COS() 。()
AR1 =R6-R3*COS(R4)/R2,
BR1 =R6*(R2+R3*COS(R4+R5)),
CR1 =R6/R2-R3*COS(R4),
DR1 =R2+R3*COS(R4*R5)),
ER1 =COS(R4)*R6/R2-R3 。
AR1 =R6-R3*COS(R4)/R2,
BR1 =R6*(R2+R3*COS(R4+R5)),
CR1 =R6/R2-R3*COS(R4),
DR1 =R2+R3*COS(R4*R5)),
ER1 =COS(R4)*R6/R2-R3 。