已知½log8(a)+log4(b)=5/2,log8(b)+log4(a^2)=7 求ab的值
问题描述:
已知½log8(a)+log4(b)=5/2,log8(b)+log4(a^2)=7 求ab的值
答
由题意可知:a>0且b>0因为½log8(a)+log4(b)=5/2,所以:log8(a)+2log4(b)=5 (1)又log8(b)+log4(a^2)=7,则:log8(b)+2log4(a)=7 (2)(1)(2)两式相加得:log8(a)+2log4(b)+log8(b)+2log4(a)=12...