如图,已知△ABC,求作一点P,使P到∠A的两边的距离相等,且PA=PB、下列确定P点的方法正确的是( )
He could see the tall chimneys of the factory ______.
一根较粗的铜线被均匀地拉伸为原长的两倍,它的电阻将会( )