logab=c代表b=ac(a為底數,logab=c=指數)a>0不為1時logaA+logaB=loga(A×B) logaA-logaB=loga(A÷B)底數相同時兩數相乘等於指數相加底數相同時兩數相除等於指數相減
log沒寫底數代表底數為10 (ex:log10=log1010=1)範例:log6=log(2×3)=log2+log3=0.7781( 2 × 3 )=10( log2 + log3 )( 100.3010 × 100.4771 )=10 (0.3010+0.4771) 6=100.7781 log2=0.3010 2=100.3010log5=log(10÷2) =log10-log2 =1-0.3010 =0.6990 5=100.6990
2...
232+514=(100.3010)32+(100.6990)14=100.3010×32+100.6990×14=109.6320+109.7860=109×100.6320+109×100.7860=109×(100.6320+100.7860) , log4=0.6020(4=100.6020)=109×(4.xxx+6.xxx)≒109×11(11位數)
已知log2=0.3010,log3=0.4771,log7=0.8451,試問..-阿摩線上測驗