Steply

Solve ln(x) = 1

Step by step, with the reason for every step · Natural logarithms · Algebra 2

Step by step

The question

Question: solve ln(x) = 1.

ln(x) = 1

e is a special number, like π.

It is about 2.718.

A log with base e is written ln.

We say "natural log".

e ≈ 2.718
ln = loge

1 Write it as a power

A log is a power.

ln(x) = 1 means: e to the power 1 is x.

ln c = k means ek = c

So x is e¹.

x = e1

Careful!

ln is log base e, not base 10.

So it is e to the power 1, not 10 to the power 1.

Careful: not x = 101 ✗

2 Use a calculator

With a calculator, e to the power 1 is about 2.7183.

e1 ≈ 2.7183

So x is about 2.718.

x ≈ 2.718

So x = e¹, about 2.718 to three decimal places.

3 Check

Let's check with a calculator.

ln 2.718 is about 1.00.

That is 1.

It works!

Check: ln(2.718) ≈ 1.00

Let's look back.

First: write it as a power.

Then: use a calculator.

Last: check.

Answer
x ≈ 2.718

Your turn

Try this one yourself, then check:

Solve ln(x) = 3
Show the answer
x ≈ 20.086

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