Question

设a=2^0.3,b=0.3²,c=log_x(x²+0.3)(x＞1),则a,b,c的大小关系是

A.a＜b＜c               B.b＜a＜c                C.c＜b＜a                 D.b＜c＜a

Answer 1

B  a=2^0.3∈(1,2),b=0.3²∈(0,1),c=log_x(x²+0.3),∴x²+0.3＞x²,且x＞1.

∴c=log_x(x²+0.3)＞log_xx²=2.∴c∈(2,+∞).故b＜a＜c.