# Definition:Sine/Historical Note

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## Historical Note on Sine

It was Hipparchus of Nicaea who first compiled tables relating the length of the arc of a circle and the length of the chord which gives rise to it, for various angles subtended by the arc. However, he did not actually define the concept of a sine as such.

The **sine** was first discussed by Aryabhata the Elder, under the name **ardha-jyā**, which means **half-chord**.

The the symbol $\sin$ for sine appears to have been invented by William Oughtred in his $1657$ work *Trigonometrie*, although some authors attribute it to Euler.

## Sources

- 1972: George F. Simmons:
*Differential Equations*... (previous) ... (next): $\S 3$: Appendix $\text A$: Euler - 1992: George F. Simmons:
*Calculus Gems*... (previous) ... (next): Chapter $\text {A}.21$: Euler ($\text {1707}$ – $\text {1783}$) - 2008: Ian Stewart:
*Taming the Infinite*... (previous) ... (next): Chapter $5$: Eternal Triangles: The origins of trigonometry