已知两个正弦量为i1=10sin(314t+90°)A、i2=10sin(628t+30°)A,则( )

已知两个正弦量为i1=10sin(314t+90°)A、i2=10sin(628t+30°)A,则( )

A.i1超前i260

B.i1滞后i260

C.i1超前i260

D.相位差无法判断

正确答案是D