【简答题】下列命令产生的数len为多少______A = rand(3,4);A(:,3) = [ ];len = length(A);
【单选题】在没有阻力和摩擦力作用时,物体的动能与势能可以相互转化,但总的机械能保持不变,这叫做
【单选题】?len(space(4)-space(3))的结果是()
【单选题】2002年SCI收录文章中,美国占32.17%,则我国约占: ( )
【简答题】Maybe the man said something which upset the lady beside him as he suddenly got a hit the chin.