When we first learn exponents, it seems straightforward:

  • should be infinitely large.
  • should be zero.
  • And since , for all finite n, maybe

Surprisingly, is not well-defined. In calculus, it’s called an indeterminate form. That means its value depends on the situation.

Understanding why requires tools from limits and sometimes L’Hôpital’s Rule. Let’s break it down.

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Let's go

Why is One to the Power of Infinity Indeterminate?

Infinity is not a number—it’s a concept. When you see something like , it usually comes from a limit where the base is approaching 1 while the exponent is growing without bound.

Example:

Here, the base (1 + x) approaches 1, while the exponent 1/x​ grows infinitely. That’s what creates the indeterminate form .

Indeterminate Forms Recap

In calculus, some expressions don’t immediately give clear answers. They’re called indeterminate forms, such as:

OperationRule / ResultNotes
∞ - ∞IndeterminateCannot be determined.
∞ × 0IndeterminateUndefined result.
∞ ÷ ∞IndeterminateDepends on context (limits).
0^0IndeterminateSometimes treated as 1, sometimes undefined.
∞^0IndeterminateNo fixed result.
1^∞IndeterminateDepends on the limit process.

These require careful analysis with limits to find their true value.

beenhere
L’Hôpital’s Rule

L’Hôpital’s Rule is one of the most powerful tools for resolving indeterminate forms.
It states:
If


gives or , then:


provided the limit on the right exists.

How to Handle One to the Power of Infinity

Suppose:

gives .

Steps:

Take the natural logarithm:

Simplify the limit:

If it becomes or , apply L’Hôpital’s Rule.

Solve for ln(y)

Exponentiate to return to y

Example

Evaluate:

Step 1: Let

Take natural logs:

Step 2: Both numerator and denominator →0. Apply L’Hôpital’s Rule:

Step 3: Exponentiate to solve for y:

Practice Questions & Solutions

1

Evaluate:

Solution

Let

Take natural logs:

Apply L’Hôpital’s Rule:

Exponentiate:

2

Evaluate:

Solution

Let

Take natural logs:

As :

Denominator:

So the form is , perfect for L’Hôpital’s Rule.

Differentiate numerator and denominator (using the chain rule):

Therefore:

At x=0:

So:

3

Evaluate:

Solution

Let

Take natural logs:

For small x, use the expansion:

Thus,

So,

Exponentiate:

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Gianpiero Placidi

UK-based Chemistry graduate with a passion for education, providing clear explanations and thoughtful guidance to inspire student success.