1, determine the method and grasp the fundamental direction.

If a straight line and a circle intersect at a certain point, then this point may be a tangent point, so it may be a tangent point.

If a straight line passes through a circle, we don't know the tangent point, so we make this straight line a vertical radius.

2. Clear your mind and take a step back.

It's easy after you do this method. Make a list of conditions, make no mistakes, and remember what to prove in the end, whether it is vertical or equal in radius. There will be a lot of recursion in using the angle. If you can't remember it, take a step back.

3. Check carefully and don't throw away meaningless points.

Don't say anything, check if there are any problems. If it is tangent, it is a big mistake to make a mistake.