A company has purchased the following intangible assets in separate transactions:
(a) A patent which expires after ten years; the company expects to make use of this patent for six years and then dispose of it
(b) A copyright which expires after 40 years; the company intends to use this copyright for 30 years, after which it is expected to be of no further value
(c) A trademark relating to a product; this trademark has an unlimited legal life but the company expects to cease manufacture of the product within three years.

Determine the useful life of each of these assets. Assuming that the company does not use the revaluation model, explain how each asset should be treated in the company's financial statements.