Project management Vs project life cycle

Greetings to all,

Computers systems validation is my Proffession.

Recently i was assigned to prepare project management and project life cycle for a project…

As a validation expert, I know very well how to organise project life cycle for various categories of Projects…

After several examinations i doubt that, The content of project management is similar to project life cycle…:confused:

Which leads to duplication of work…

Can anybody please guide me…

what is the need of maintaining both project management and project life cycle documents for a project…

Regards
Anusha Kodali