Question

对数函数公式表

全点 快点 准确点

Answer 1

1、a^(log(a)(b))=b 2、log(a)(a^b)=b 3、log(a)(MN)=log(a)(M)+log(a)(N); 4、log(a)(M÷N)=log(a)(M)-log(a)(N); 5、log(a)(M^n)=nlog(a)(M) 6、log(a^n)M=1/nlog(a)(M) 推导 1、因为n=log(a)(b)代入则a^n=b即a^(log(a)(b))=b。 2、因为a^b=a^b 令t=a^b 所以a^b=tb=log(a)(t)=log(a)(a^b) 3、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)] =(M)*(N) 由指数的性质 a^[log(a)(MN)] = a^{[log(a)(M)] + [log(a)(N)]} 两种方法只是性质不同,采用方法依实际情况而定 又因为指数函数是单调函数所以 log(a)(MN) = log(a)(M) + log(a)(N) 4、与3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) 5、与(3)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(b^m)÷ln(a^n) 换底公式的推导 设e^x=b^m,e^y=a^n 则log(a^n)(b^m)=log(e^y)(e^x)=x/y x=ln(b^m),y=ln(a^n) 得log(a^n)(b^m)=ln(b^m)÷ln(a^n) 由基本性质4可得 log(a^n)(b^m) = [m×ln(b)]÷[n×ln(a)] = (m÷n)×{[ln(b)]÷[ln(a)]} 再由换底公式 log(a^n)(b^m)=m÷n×[log(a)(b)]

Answer 2

没悬赏啊？？？
log（MN)=logA^M+A^N

Answer 3

LOGa(MN)=LOGaM+LOGaN
LOGa(M/N)=LOGaM-LOGaN
LOGa(M^n)=nLOGaM
LOGaN=LOGcN/LOGc a

Answer 4

Log(MN)=LOGaM+LOGaN

Answer 5

赞楼上