A.a＞b且c=dac＞bd                                                B.a＞b

C.a³＞b³且ab＞0                                           D.a²＞b²且ab＞0

A.若a＞b，k∈N^*，则a^k＞b^k                                          B.a－b＜0，c＞1

C.a＞b，c＞d(a－b)²＞(d－c)²                                 D.a＞b＞0，c＞d＞0

ba

命题②：a＞b＞0，c＞d＞0；

命题③：且c＞0a＞b；

命题④：a＜b(n∈N^*)a＜b.这些命题中真命题的个数是

A.1                  B.2                  C.3                  D.4

A.若ac＞bc，则a＞b                                                B.若ac=bc，则a=b

C.若a＞b，则                                                D.若ac²＞bc²，则a＞b

A.(0，)          B.(－，)              C.(0，π)                   D.(－，π)

①a＞b＞1  ②a＞ba²＞b²  ③a³＞b³a＞b  ④a＞ba²ⁿ⁺¹＞b²ⁿ⁺¹(n∈N^*)

A.1                                 B.2                                C.3                        D.4

A.                  B.ab＞b²                       C.                          D.＜1