神马品牌网明珠小学对口小区:超越方程 求解
来源：百度文库 编辑：神马品牌网 时间：2024/04/19 11:11:59
x+log[2,(2^x-31)]=5
答案x=5
求过程...
log[2,(2^x-31)]
底数2
真数2^x -31
答案x=5
求过程...
log[2,(2^x-31)]
底数2
真数2^x -31
x + log[2,(2^x-31)] = 5
log[2,(2^x-31)] = 5 - x
2^x - 31 = 2^(5 - x)
2^x - 31 = 2^5/2^x
令 u = 2^x
u^2 - 31u - 32 = 0
(u - 32)(u - 1) = 0
u = 32 ................x = 5
u = 1 ..................x = 0 ....... 2^x - 31 < 0