Ramanujan proposed additive formulae of theta functions that are related to modular equations about infinite products. Employing these formulaes, we derived some identities on infinite products. In the same spirit, we also could present elementary and simple proofs of certain Ramanujan's modular equations on infinite products.
"A Note on Certain Modular Equations about Infinite Products of Ramanujan." Abstr. Appl. Anal. 2013 (SI53) 1 - 5, 2013. https://doi.org/10.1155/2013/826472