f (x)定义在(0,+∞)上的非负可导函数,且满足≤0,对任意的正数a,b,若a<b,则必有 ( ▲ )
A.bf (b)≤af (a) | B.bf (a)≤af (b) | C.af (a)≤bf (b) | D.af (b)≤bf (a) |
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f (x)定义在(0,+∞)上的非负可导函数,且满足≤0,对任意的正数a,b,若a<b,则必有 ( ▲ )
A.bf (b)≤af (a) | B.bf (a)≤af (b) | C.af (a)≤bf (b) | D.af (b)≤bf (a) |