文档介绍：要点梳理 (1)对数的定义如果 a x=N(a>0且a≠1),那么数 x叫做以 a为底 N的对数,记作_________, 其中____ 叫做对数的底数,____ 叫做真数. aN § 对数与对数函数 x=log aN 基础知识自主学习 Evaluation only. Evaluation only. Created with Client Profile . Created with Client Profile . Copyright 2004-2011 Aspose Pty Ltd. Copyright 2004-2011 Aspose Pty Ltd. (2)几种常见对数 (1)对数的性质① =_____; ②log aa N=_____( a>0且a≠1). 对数形式一般对数常用对数自然对数特点底数为 a(a>0且a≠1) 底数为____ 底数为____ 记法_______ ______ ______ eln N lg N log aN10 N aa logNN Evaluation only. Evaluation only. Created with Client Profile . Created with Client Profile . Copyright 2004-2011 Aspose Pty Ltd. Copyright 2004-2011 Aspose Pty Ltd. (2)对数的重要公式①换底公式: ( a,b均大于零且不等于1); ②推广 log ab·log bc·log cd= ______. (3) 对数的运算法则如果 a>0且a≠1,M>0, N>0, 那么①log a(MN)=______________; ② =______________; b NN a ab log log log ?, log 1 loga b b a?log adlog aM+log aNlog aM-log aN N M a log Evaluation only. Evaluation only. Created with Client Profile . Created with Client Profile . Copyright 2004-2011 Aspose Pty Ltd. Copyright 2004-2011 Aspose Pty Ltd. ③log aM n=___________( n∈R); ④ nlog aM . log logM m nM a na m?图象 a>10<a<1 Evaluation only. Evaluation only. Created with Client Profile . Created with Client Profile . Copyright 2004-2011 Aspose Pty Ltd. Copyright 2004-2011 Aspose Pty Ltd. 性质(1) 定义域:__________ (2) 值域:_____ (3) 过点_______, 即x=___ 时,y=___ (4) 当x>1时,_____ 当0<x<1时,_______ (5) 是(0,+∞)上的___________ (4) 当x>1时,_______ 当0<x<1时,_____ (5) 是(0,+∞)上的____________ R (0, +∞)(1, 0) y>0y>0 y<0 y<0 10 增函数减函数 y=a x与对数函数_________ 互为反函数,它们的图象关于直线_________ 对称. y=log axy=x Evaluation only. Evaluation only. Created with Client Profile . Created with