Kerala school of astronomy and mathematics
The theorems were stated without proof , but proofs for the series for sine , cosine , and inverse tangent were provided a century later in the work "Yuktibhasa" , written in Malayalam , by Jyesthadeva , and also in a commentary on "Tantrasangraha" . 
<triplet> Yuktibhasa <subj> Malayalam <obj> language of work or name