关于高中数学log特殊值,高中数学log特殊值怎么算这个很多人还不知道,今天小周来为大家解答以上的问题,现在让我们一起来看看吧!

1、【非原创】本性质:1.a^(log(a)(b))=b2.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1.这个就不用推了吧,直接由定义式可得(把定义式中的[n=log(a)(b)]带入a^n=b)2.MN=MN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)其他性质: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)性质二:(不知道什么名字)log(a^n)(b^m)=m/n[log(a)(b)]推导如下由换底公式[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)=[nln(a)]/[mln(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)公式三: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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