Leibniz's Formula for Pi/Historical Note

Historical Note on Leibniz's Formula for Pi

Leibniz discovered his formula for $\pi$ in $1673$.

He took great pleasure and pride in this discovery.

It's as if, by this expansion, the veil which hung over that strange number had been drawn aside.

Simple as it is, Leibniz's Formula for Pi is inefficient, in that it needs hundreds of terms in order to calculate a few decimal places.

Some sources ascribe this formula to James Gregory.

1937: Eric Temple Bell: Men of Mathematics ... (previous) ... (next): Chapter $\text{VII}$: Master of All Trades
1986: David Wells: Curious and Interesting Numbers ... (previous) ... (next): $3 \cdotp 14159 \, 26535 \, 89793 \, 23846 \, 26433 \, 83279 \, 50288 \, 41972 \ldots$
1992: George F. Simmons: Calculus Gems ... (previous) ... (next): Chapter $\text {A}.19$: Leibniz ($\text {1646}$ – $\text {1716}$)
1992: George F. Simmons: Calculus Gems ... (previous) ... (next): Chapter $\text {B}.13$: How Leibniz Discovered his Formula $\pi / 4 = 1 - \frac 1 3 + \frac 1 5 - \frac 1 7 + \cdots$
1997: David Wells: Curious and Interesting Numbers (2nd ed.) ... (previous) ... (next): $3 \cdotp 14159 \, 26535 \, 89793 \, 23846 \, 26433 \, 83279 \, 50288 \, 41971 \ldots$