# Category Archives: Challenge

## Trigonography Challenge: Series for Cotangent and Cosecant

Sine and cosine have their pinwheel. Secant and tangent have their zig-zag. These raise an obvious question, to which I currently have no answer.I offer it as the first-ever Trigonography Challenge: What trigonograph depicts the (Laurent) series for cotangent and cosecant? $$\large \begin{align} \cot\theta &\;=\; \frac{1}{\theta} \;-\; \frac{1}{3}\theta \;-\; \frac{1}{45}\theta^3 \;-\; \frac{2}{945}\theta^5 \;-\; \cdots \\[6pt] […]

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