学帮网对数函数
来源：学生作业学帮网 编辑：学帮网 时间：2024/05/20 16:49:14
对数函数
log(1/2)x
=lnx/ln(1/2)
=lnx/(-ln2)
=-lnx/ln2
=-long(2)x
y = log(1/2) (x)
= log(2) (x) / log(2) (1/2) (利用换底公式, 取公底为2)
= log(2) (x) / log(2) (2^(-1))
= log(2) (x) / -log(2) (2)
= log(2) (x) / (-1)
= -log(2) (x)
已知y=log(1/2)x,那么x=(1/2)^y,由此x=2^(-y)
对上式再取对数，得-y=log(2)x,那么y=-log(2)x