 The function μ was found by Ramanujan in his lost notebook.These are related to the functions listed in the section on order 8 functions by

Ramanujan mentioned four order-3 mock theta functions in his letter to Hardy, and listed a further three in his lost notebook, which were rediscovered by G. N. Watson.proved the relations between them stated by Ramanujan and also found their transformations under elements of the modular group by expressing them as Appell–Lerch sums.