[填空题]
Two piano strings arnpcun*8ne s*1aw qawd79u;9 jm 0 tr,w bei7 kfy3s 2v1*uwp3we supposed to be vibrating at 132 Hz, but a piano tuner hears three beats every 2.0 s when they are played together. (a) If one is vik w23vs*ipye1wf3ub 7 brating at 132 Hz, what must be the frequency of the other ? Hz Hz
(b) By how much (in percent) must the tension be increased or decreased to bring them in tune? % increase %decrease