Pi Formula: The Ugly Ninja
Ramanujan's ugly-looking but extremely fast-converging series for 1/π, as a turnip-faced ninja.
Use this cartoon
Free for classrooms, worksheets, slides and other non-commercial use under CC BY-NC 4.0, with credit to Ben Orlin.
Cartoon by Ben Orlin, Math with Bad Drawings. https://cartoons.mathwithbaddrawings.com/2016-03-14-pi-formula-the-ugly-ninja/ (CC BY-NC 4.0)Transcript
"The Ugly Ninja" "a face like a turnip too shriveled to pick — but lethally quick." 1/π = (2√2/9801)(1103 + 4·3·2·1(1103 + 26390·1)/((1!)⁴·396⁴) + …)