数学对数函数的运算
问题描述:
数学对数函数的运算
答
对数的运算法则及变式法则答:若a^b=C,(a>0,a≠1),则b=log(a)C.把b=log(a)C代回去,便得a^log(a)C=C.(此式很有用)log(a)MN=log(a)M+log(a)Nlog(a)(M/N)=log(a)M-log(a)Nlog(a)(M^n)=nlog(a)Mlog(a)M=log(b)M/log(b)a.(换底公式)log(a^n)(M^n)=log(a)M此式由换底公式演化而来:log(a^n)(M^n)=log(a)(M^n)/log(a)(a^n)=nlog(a)M/nlog(a)a=log(a)M.例如:log(8)27=log(2³)3³=log(2)3再如:log(√2)√5=log(2)5.这些公式度可倒过来用.