Chapter 5 - Exponential and Logarithmic Functions - 5.4 Logarithmic Functions - 5.4 Assess Your Understanding - Page 298: 137

If the base is $1$, then for $\log_1 x$, apart from $x=1$, there would be no solution and if $x=1$ then all real numbers would be solutions which wouldn't make a lot of sense to use.

If the base is $1$, then for $\log_1 x$, apart from $x=1$, there would be no solution and if $x=1$ then all real numbers would be solutions which wouldn't make a lot of sense to use.