摘要: Armour (British English) or armor (American English) is a covering to protect an object, individual, or vehicle from damage, especially direct contact 阅读全文
posted @ 2022-01-26 23:29 华容道专家 阅读(343) 评论(0) 推荐(0)
摘要: 两个向量a和b, a点积b = 模a * 模b * cos(夹角) 二维我想可以用cos(alpha - beta) = cos(alpha)cos(beta) + sin(alpha)sin(beta)来证明。 上述合角公式用向量来证明很方便,可惜循环论证了。 这里有别的证明方式:Sin, Cos 阅读全文
posted @ 2022-01-26 15:48 华容道专家 阅读(122) 评论(0) 推荐(0)
摘要: An archive is an accumulation of historical records - in any media - or the physical facility in which they are located. Archives contain primary sour 阅读全文
posted @ 2022-01-26 09:58 华容道专家 阅读(231) 评论(0) 推荐(0)