(The) Rsine is positive or negative in the upper or lower halves (of the quadrants); and its Rcosine is positive, negative, negative, and positive (respectively) according to the successive quadrants.
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Datta, Bibhutibhushan, and Avadesh Narayan Singh.———. ‘Hindu Trigonometry’ (revised by K.S. Shukla). Indian Journal of History of Science 18 (1) (1983): pp. 39-108. quoted from Bhaskar Kamble, The Imperishable Seed: How Hindu Mathematics Changed the World and why this History was Erased, Garuda Prakashan Private Limited, 2022 ISBN 9798885750189