Study Guides/Maths/Log Infinity Value
Study Guide · Maths

What is the Value of log(∞)?

log(∞) = ∞ (Infinity). The logarithm function grows without bound as its argument approaches infinity, although it grows very, very slowly compared to other functions.

Question (Click to Flip)

Is log(0) defined?

Answer

No. log(0) is undefined. The logarithm can only be taken of positive numbers. As x approaches 0 from the positive side, log(x) approaches negative infinity (−∞).

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Key Facts

The logarithm is the inverse of the exponential function. Just as e^(∞) = ∞, the inverse gives ln(∞) = ∞. The logarithm grows so slowly that it is used in computer science (Big-O notation) to describe the most efficient algorithms.

Explanation

The common logarithm (log base 10) or natural logarithm (ln) of infinity is not defined as a fixed number — it diverges to infinity.

Mathematically:

lim(x→∞) log(x) = ∞

This means as x becomes larger and larger without limit, log(x) also becomes larger without limit — it just does so very slowly.

Examples:

  • log(10) = 1
  • log(1,000) = 3
  • log(1,000,000) = 6
  • log(10⁶⁰) = 60

Even for astronomically large numbers, log gives finite values, but ultimately, as x → ∞, log(x) → ∞.

Special Logarithm Values to Remember

ExpressionValue
log(1)0
log(10)1
log(0⁺)-∞
log(∞)
ln(e)1
log(0)Not Defined (undefined, approaches -∞)

Questions and Answers

Is log(0) defined?+

No. log(0) is **undefined**. The logarithm can only be taken of positive numbers. As x approaches 0 from the positive side, log(x) approaches **negative infinity** (−∞).

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