3.给出以下四个问题:
(1)输入x,输出|x-2|的值.
(2)求面积为6的等边三角形的边长.
(3)求三个数a,b,c中的最小数.
(4)求函数f(x)={■(1/x "," x>0"," @√("-" x) "," x≤0)┤的函数值.
其中不需要用条件分支结构来描述其算法的有( )
A.1个 B.2个 C.3个 D.4个
答案:A
4.执行如图所示的程序框图,若输出结果为3,则可输入的实数x值的个数为( )
A.1 B.2 C.3 D.4
解析:令log2x=3,得x=8(符合题意);
令x2-1=3,得x=±2(符合题意).
故可输入的实数有-2,2,8共3个数.
答案:C
5.任给x的值,计算函数y={■(1"," x<1"," @2"," x=1"," @3"," x>1)┤中y值的程序框图如下图所示,其中①②③分别是( )