Question

一个数学问题，十万火急！！！在线等

已知Log以2为底3等于a，Log以3为底7等于b，试用a、b表示Log以14为底56

Answer 1

log2 3=a
lg3/lg2=a
lg3=alg2
log3 7=b
lg7/lg3=b
lg7=blg3=ablg2

log14 56=lg56/lg14=(lg7+3lg2)/(lg2+lg7)=(ablg2+3lg2)/(lg2+ablg2)
=(ab+3)/(1+ab)

Answer 2

log2 3=a
lg3/lg2=a
lg3=alg2
log3 7=b
lg7/lg3=b
lg7=blg3=ablg2

log14 56=lg56/lg14=(lg7+3lg2)/(lg2+lg7)=(ablg2+3lg2)/(lg2+ablg2)
=(ab+3)/(1+ab)
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