Mercator series
The Mercator series gives a taylor series for the natural logarithm
Explanation
The identity for power series is
We convert this into a more useful formula and substitute r = – t
Now we divide by 1 + t and get
This is
For |t| < 1 and n → ∞ holds tn+1→ 0, so that
This is an elegant formula that we can easily integrate
Calculating this inverse derivative of the logarithm then gives
Example 1
You can see that ln (1) = 0, because
ln (1) = 0 − 0 + 0 − 0 + ⋯ = 0
HistoryThe German mathematician Nicholas Mercator used the Latin name "logarithmus naturalis" in his treatise Logarithmo-technica in 1668. |