在高考中,带电粒子在磁场中的匀速圆周运动问题是一个热点问题,而带电粒子在磁场中做匀速圆周运动的极值问题是个难点,人们在对相切点的应用时,用得是很多的,但在解答过程中往往忽略对缩放与旋转的有效应用,从而导致学生在每次解答此类问题时总是感觉不是很理解,从而产生对此类问题的畏惧。我在教学中总结了一条方法应对此类问题很有效,利用好相切、缩放与旋转能达到对此类 In the college entrance examination, the uniform circular motion of charged particles in the magnetic field is a hot issue, and the extreme problem of the charged particles doing uniform circular motion in the magnetic field is a difficult task. When using tangent points, people use a lot of them However, in the process of answering, the effective application of scaling and rotation are often neglected, which leads students to feel uncomfortable with such problems every time they answer such questions. In teaching, I summed up a way to deal with such problems is very effective, the use of good tangent, scaling and rotation to achieve such