数的换底公式:logab=logcb/logca(a>0,且a≠1;c>0,且c≠1,b>0).换底公式在对数的运算中有着十分重要的作用,应用灵活多变,掌握换底公式及应用,有利于提高恒等变形能力及快速解题能力,课本中没有给出证明,现就换底公式及应用分析如下,供参考. The logarithm of logarithm for logarithm is logab = logcb / logca (a> 0 and a ≠ 1; c> 0 and c ≠ 1, b> 0) The application of flexible and change, to master the formula for the replacement and application, is conducive to improving the ability of equal deformation and rapid problem-solving skills, no proof is given in the textbook, now on the replacement formula and application analysis is as follows for reference.