课时分层作业(十七)对数(建议用时:60分钟)合格基础练一、选择题1已知f(ex)x,则f(3)()Alog3 eBln 3Ce3 D3eBf(ex)x,由ex3得xln 3,即f(3)ln 3,选B.2方程的解是()A9 B.C. D.D22,log3x2,x32.3log3 ()A4 B4C DB令log3t,则3t34,t4.4log5(log3(log2x)0,则等于()A. B.C. D.Clog5(log3(log2x)0,log3(log2x)1,log2x3,x238,5下列各式:lg(lg 10)0;lg(ln e)0;若10lg x,则x10;若log25x,则x5.其中正确的个数有()A1个 B2个C3个 D4个B对于,lg(lg 10)lg 10,对;对于,lg(ln e)lg 10,对;对于,10lg x,x1010,错;对于,log25x,x255.所以只有正确二、填空题6log333log32_3log333log32123.8使log(x1)(x2)有意义的x的取值范围是_(1,2)(2,)要使log(x1)(x2)有意义,则x1且x2.三、解答题等级过关练