求值!log2(cos湃/9)+log2(cos2湃/9)+log2(cos4湃/9)答案是-3,『湃就是3.14159

来源：学生作业帮编辑：作业帮分类：数学作业时间：2024/05/10 05:12:40

求值!log2(cos湃/9)+log2(cos2湃/9)+log2(cos4湃/9)答案是-3,『湃就是3.1415926...』

原式=log2(cosπ/9cos2π/9cos4π/9)
=log2(sinπ/9cosπ/9cos2π/9cos4π/9)/(sinπ/9)
=log2(sin2π/9cos2π/9cos4π/9)/(2sinπ/9)
=log2(sin4π/9cos4π/9)/(4sinπ/9)
=log2(sin8π/9)/(8sinπ/9)

(log2 9)/(log2 8) = 2/3(log2 3) log8(9)*log2(3) log8^9/log2^3的值是 log8 9/log2 3的值是? (log3^4+log5^2)(log2^9+log2^根号3) log8(9)除以log2(3) (log8 9/log2 3)=? 求(log2^3+log8^9) LOG2^3=A,LOG2^5=b,则log2^9/5值是多少 log2(12)-log4(9)的值是 log2^x=log4^9 log2 12÷log2 3+log3 9 -log27 64 （空格前面是底数后面是对数）