用三角函数证明画法几何中正五边形的画法

画法几何中介绍了正五边形的作图方法,但画法的准确性值得探究。用三角函数的知识证明了正五边形画法的准确性,并探究了正五边形的其他作图方法。

The drawing method of a regular pentagon has been introduced among the geometry about technique of drawing, but the exact is worth to exploration. This text proved the exact of the drawing method of a regular pentagon with knowledge of circular functions. And look into the other drawing method about a regular pentagon.