已知函数f(x)=,若a,b,c互不相等,设f(a)=f(b)=f(c),则abc的取值范围 ( )
A.B C. D.
A.(x+B (log2x)′= C.(3x)′=3xlog3e D.(x2cosx)′=-2xsinx
A.30°B 45° C.60° D.135°
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