ile:24 等差数列习题1.flv file:58 综合例题讲解1.flv file:07三角函数的化简.flv file:19 解三角形的习题4.flv file:15 解三角形-基本公式、化简原理.flv file:82 关于导数的练习题.flv file:计数原理.doc file:选修(几何证明选讲).doc