Dave Richeson on X: "Euler proved that π/4=arctan(1/2)+arctan(1/3), which can be used for computing digits of π (using the arctangent series). I wondered if I could prove it without using a trig
How do you evaluate arctan(-1) using a unit circle? | Socratic
I love maths - arctan(1/3)+arctan(1/2)=arctan1...As the total angle made by green and blue angle is nothing but an angle created by diagonal of a square (which is π/4). | Facebook
How to show that arctan 1/3+arctan 1/5=arctan 4/7 - Quora
How do you evaluate arctan(-1) without a calculator? | Socratic