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# Mathematics in Ancient and Medieval India c8.40

Mathematics in Ancient and Medieval India c8.40

- **Language:** English

### [c8.40](https://indike.org/pramana/ins.science.bag-1979.c8.40)

The R Sine of the \*bhūja\* is defined to be the R Sine of the corresponding anomaly and the R Sine of the \*koṭi\* is defined to be the R Cosine of the corresponding anomaly. The R Sine is positive in the first and second quadrants and negative in the third and fourth quadrants. The R cosine is positive in the first and fourth quadrants and negative in the second and third quadrants. Then we have, $R Sin AP₁ = P₁E R Cos AP₁ = P₁F$ $R Sin AP₂ = P₂H R Cos AP₂ = -P₂G$ $R Sin AP₃ = -P₃M R Cos AP₃ = -P₃N$ $R Sin AP₄ = -P₄S R Cos AP₄ = PT₄$ This is equivalent to $R Sin (90⁰ + A) = R Sin (90⁰ - A) = R Cos A$ $R Sin (180⁰ + A) = -R Sin A$ $R Sin (270⁰ + A) = -R Sin (90′ - A) = -R Cos A$ $Where A \< 90⁰$ Similarly R Cosine formulae can also be deduced.

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Source: [https://indike.org/pramana/ins.science.bag-1979.c8.40](https://indike.org/pramana/ins.science.bag-1979.c8.40) · Pramāṇa
