某些酵母菌上下两细胞连接处呈细腰状,通常称为:()A.有隔菌丝; B.无隔菌丝; C 发布时间:2017-06-27 00:53 │ 来源:www.tikuol.com 题型:单项选择题 问题: 某些酵母菌上下两细胞连接处呈细腰状,通常称为:()A.有隔菌丝;B.无隔菌丝;C.假菌丝;D.异核菌丝
题型:单项选择题 设函数f(x)=13ax3+12bx2+cx(a,b,c∈R,a≠0)的图象在点(x,f(x))处的切线的斜率为k(x),且函数g(x)=k(x)-12x为偶函数.若函数k(x)满足下列条件:①k(-1)=0;②对一切实数x,不等式k(x)≤12x2+12恒成立.(Ⅰ)求函数k(x)的表达式;(Ⅱ)求证:1k(1)+1k(2)+…+1k(n)>2nn+2(n∈N*). 查看答案
题型:单项选择题 A project has the following characteristics: payback of $2,000, profit of $1,000, project cost of $800, life cycle cost of $1,200. What is the benefit cost ratio of the projectA.2.50.B.1.25.C.1.67.D.0.83. 查看答案