Are $log_1 1$ and $log_0 0$ indeterminate forms?

Are $\log_1 1$ and $\log_0 0$ indeterminate forms?

Whenever I ask someone about these indeterminate forms, they deny by saying either $\log$ is neither defined at base $0$ nor at base $1$, or they say $\log$ is a function so these must not be included in fundamental indeterminates.

But, we know division by zero is not defined, yet $0/0$ is indeterminate; and many others. And, actually, $\log$ is more a binary-operator that is the inverse operation of power/exponent operator.

Answer

I think that your difficulty comes from a confusion regarding what an "indeterminate form" is. Indeterminate forms show up in analysis via naive substitution when computing limits. For example, we might naively compute

$$\lim_{x\to 0} \frac{x^2}{x} = \frac{\lim_{x\to 0} x^2}{\lim_{x\to 0} x} = \frac{0}{0}.$$
Since this last expression is undefined, we might say that the limit is "indeterminate of the form $\frac{0}{0}$." When this kind of naive substitution leads to an undefined expression, it is necessary to be a bit more clever in the evaluation of the limit. In this case,
$$\lim_{x\to 0} \frac{x^2}{x} = \lim_{x\to 0} x = 0.$$
Techniques for working with indeterminate forms include results such as L'Hospital's rule, applying algebraic transformations, and so on.

In the case of "the logarithm base 0", $\log_0(x)$ is undefined. This expression doesn't make sense. If this expression were defined, then it must be equal to some number, say $y$. Then

$$\log_0(x) = y \implies x = 0^y = 0.$$
But $0^y = 0$ for any positive value of $y$. Hence the expression $\log_0(x)$ is not well defined, as there is a not a unique value of $y$ which gets the job done. On the other hand, we can consider limits of expressions of the form $\log_b(a)$ as $b$ tends to zero and $a$ either tends to zero or diverges to infinity. Such limits can be said to be "indeterminate of the form $\log_0(0)$" or "indeterminate of the form $\log_0(\infty)$, but this does not mean that they are equal to either of these expressions (anymore than $\lim_{x\to 0} x^2/x = 0/0$).

Such limits typically require more careful analysis, again using algebraic tools, L'Hospital's rule and other results from analysis, bounding with estimates, or direct $\varepsilon$-$\delta$ style computation. Limits involving logarithms are discussed in greater detail in J.G.'s answer.

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In short, when we say that "the limit is indeterminate of the form $X$", we are saying that if we try to evaluate the limit by naive substitution, then we get the expression $X$, where $X$ is some undefined expression like $\frac{0}{0}$, $\log_0(0)$, or $1^\infty$. Such limits cannot be evaluated by naive substitution, and require other techniques.