对数运算公式大全集(对数运算公式大全)
大家好,小房来为大家解答以上的问题。对数运算公式大全集,对数运算公式大全这个很多人还不知道,现在让我们一起来看看吧!
1、定义: 若a^n=b(a>0且a≠1) 则n=log(a)(b) 基本性质: a^(log(a)(b))=b 2、log(a)(MN)=log(a)(M)+log(a)(N); 3、log(a)(M÷N)=log(a)(M)-log(a)(N); 4、log(a)(M^n)=nlog(a)(M) 推导 因为n=log(a)(b),代入则a^n=b,即a^(log(a)(b))=b。
2、 2、MN=M×N 由基本性质1(换掉M和N) a^[log(a)(MN)] = a^[log(a)(M)]×a^[log(a)(N)] 由指数的性质 a^[log(a)(MN)] = a^{[log(a)(M)] + [log(a)(N)]} 又因为指数函数是单调函数,所以 log(a)(MN) = log(a)(M) + log(a)(N) 3、与(2)类似处理 MN=M÷N 由基本性质1(换掉M和N) a^[log(a)(M÷N)] = a^[log(a)(M)]÷a^[log(a)(N)] 由指数的性质 a^[log(a)(M÷N)] = a^{[log(a)(M)] - [log(a)(N)]} 又因为指数函数是单调函数,所以 log(a)(M÷N) = log(a)(M) - log(a)(N) 4、与(2)类似处理 M^n=M^n 由基本性质1(换掉M) a^[log(a)(M^n)] = {a^[log(a)(M)]}^n 由指数的性质 a^[log(a)(M^n)] = a^{[log(a)(M)]*n} 又因为指数函数是单调函数,所以 log(a)(M^n)=nlog(a)(M)基本性质4推广log(a^n)(b^m)=m/n*[log(a)(b)]推导如下:由换底公式(换底公式见下面)[lnx是log(e)(x)e称作自然对数的底] log(a^n)(b^m)=ln(a^n)÷ln(b^n)由基本性质4可得log(a^n)(b^m) = [n×ln(a)]÷[m×ln(b)] = (m÷n)×{[ln(a)]÷[ln(b)]}再由换底公式log(a^n)(b^m)=m÷n×[log(a)(b)] --------------------------------------------(性质及推导 完)其他性质[编辑本段]性质一:换底公式log(a)(N)=log(b)(N)÷log(b)(a)推导如下:N = a^[log(a)(N)]a = b^[log(b)(a)]综合两式可得N = {b^[log(b)(a)]}^[log(a)(N)] = b^{[log(a)(N)]*[log(b)(a)]}又因为N=b^[log(b)(N)]所以 b^[log(b)(N)] = b^{[log(a)(N)]*[log(b)(a)]}所以 log(b)(N) = [log(a)(N)]*[log(b)(a)] {这步不明白或有疑问看上面的}所以log(a)(N)=log(b)(N) / log(b)(a)公式二:log(a)(b)=1/log(b)(a)证明如下:由换底公式 log(a)(b)=log(b)(b)/log(b)(a) ----取以b为底的对数log(b)(b)=1 =1/log(b)(a) 还可变形得: log(a)(b)×log(b)(a)=1。
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