Expanding Logarithms Calculator

Expanding Logarithms

Apply logarithm laws to expand complex expressions into sums and differences.

Last updated: March 2026 | By ForgeCalc Engineering

Original Expression
log_10((a * b) / c)
Expanded Form
log_10(a) + log_10(b) - log_10(c)

What is Expanding Logarithms?

Expanding logarithms is the process of using the laws of logarithms to break down a single logarithmic expression containing products, quotients, or powers into multiple simpler logarithmic terms.

This is a crucial skill in algebra and calculus, as it allows you to simplify complex equations, solve for variables in exponents, and differentiate logarithmic functions more easily.

The Three Laws

Product Rule

log(xy) = log(x) + log(y)

Quotient Rule

log(x/y) = log(x) - log(y)

Power Rule

log(xⁿ) = n * log(x)

Example Calculation

Expand log(x²y / z³):

1. Apply Quotient Rule: log(x²y) - log(z³)

2. Apply Product Rule: log(x²) + log(y) - log(z³)

3. Apply Power Rule: 2log(x) + log(y) - 3log(z)

Final Answer: 2log(x) + log(y) - 3log(z)

Frequently Asked Questions

Can I expand log(x + y)?

No. There is no law for the logarithm of a sum. You can only expand products, quotients, and powers.

What is 'ln'?

ln stands for the natural logarithm, which is a logarithm with base e (Euler's number, ≈ 2.718).

Does the base change during expansion?

No. All expanded terms must keep the same base as the original expression.

What is condensing logarithms?

Condensing is the opposite of expanding. It involves taking multiple log terms and combining them into a single log expression.

What is the product rule for logarithms?

The product rule states: log_b(xy) = log_b(x) + log_b(y). When you have a product inside a logarithm, you split it into a sum of logarithms.

What is the quotient rule for logarithms?

The quotient rule states: log_b(x/y) = log_b(x) - log_b(y). When you have a fraction inside a logarithm, you can split it into a difference of logarithms.

What is the power rule for logarithms?

The power rule states: log_b(x^n) = n·log_b(x). An exponent inside the logarithm can be brought out front as a coefficient.

Can you expand logarithms with different bases?

Yes, as long as all logarithms in the expression have the same base. If bases differ, you would need to convert them first using the change of base formula.

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