In the context of prototyping during the design phase of the systems development life cycle (sdlc), a shows users how a particular task that was not technically feasible or appears to be unfeasible can be done.

The answer is "proof-of-concept prototype".

A proof of concept is a framework structured simply to exhibit the usefulness of a solitary or little arrangement of standards to be coordinated into different frameworks. True ease of use isn't viewed as while making a proof of idea since incorporation with other faulty advancements isn't just tedious, however may weaken the capacity to decide whether the standard idea is practical.  

A prototype is a first endeavor at making something that may be true usable. It is assumed that you may misunderstand things all the while, yet finding that out is the standard motivation behind a model. A model will have all (or almost all) of the usefulness of the completed item, however will for the most part not be as proficient, tastefully satisfying, or strong.