Deduct your notebook from income tax when you have almost finished your studies

I bought a notebook for 1000 euro. My studies only last 3 months (= end of the semester).

Can I still deduct the notebook from my tax? Is that possible for 2020 as well as for 2021?

Do you have to have paid taxes to think about claiming income-related expenses or special expenses in the 1st degree, if not there may be a loss carryforward.
It depends on when you bought the notebook.
Do you have to somehow make the tax office credible about the proportions in which you use it privately and at school.

When these points are met, then one can think about it.