
10.B【解析】若a=5,k=0,则:满足循环的条件,S=一1,k=1;满足循环的条件,S=,k=2;满足循环的条件,S=2,k=3;满足2循环的条件,S=一1,k=4;满足循环的条件,S2,k=5;当k=5时,不满足进行循环的条件,此时输出结果S=,故选B
11.A【解折]令工=0得f(0)=1,所以f(x)=c一x,将2a-1-≥f(x)化筒得2a一1≥e0一x ,令g(x)=e-x 则g(x)=e一1 x,令h(x)=g'(x)=e2一1 x,h'(x)=e 1>0,∴g'(x)为增函数,当x>0时g'(x)>g'(0)=0,g(x)为增函数,g(x)>g(0)=1;当x<0时g(x)g(0)=1;因此g(x)最小值为1,从而2a一1≥1,即a≥1,故选A.