I´m a study girl of engineer and i want to use this app

Hi,

Welcome to Prime 8

Trial version 30 days full Prime 8 then reverts to Prime Express check the box to talk to sales.  Start here
https://www.mathcad.com/en/education

https://www.mathcad.com/en/try-and-buy/mathcad-express-free-download

Full version USA and Canada
https://store.ptc.com/store/ptc/DisplayCategoryProductListPage/categoryID.5321800

Student version? Available in USA and Canada
https://store.ptc.com/store/ptc/en_US/list/ThemeID.21925700/categoryID.10011800

International resellers - has a search by country option on left hand side.
https://www.ptc.com/en/partners/partner-search

Cheers

Terry