若log16(9)=a,18^b=5,用a,b表示log36(45).
问题描述：
若log16(9)=a,18^b=5,用a,b表示log36(45).
答
a=log16(9)=(2ln3)/(4ln2) b=(ln5)/(ln18)=(ln5)/(2ln3+ln2)log36(45)=(2ln3+ln5)/(2ln2+2ln3)=1/(ln2/ln3+1) + [(ln5)/(2ln3+ln2)]/[(2ln2+2ln3)/(2ln3+ln2)]=1/(2a+1)+b/[(2+2ln3/ln2)/(2ln3/ln2+1)]=1/(2a+1)+b/[...答案是（4a+b)/(4a+2)呀？log36(45)=(2ln3+ln5)/(2ln2+2ln3)这里开始改→=（ln3/ln2)/(ln3/ln2+1) + [(ln5)/(2ln3+ln2)]/[(2ln2+2ln3)/(2ln3+ln2)]=2a/(2a+1)+b/[(2+2ln3/ln2)/(2ln3/ln2+1)]=2a/(2a+1)+b/[(2+4a)/(4a+1)]=(4a+b+4ab)/(2+4a) 亲，真算不到你那个答案...话说用计算器验算了一下，的确不是(4a+b)/(4a+2)...