Help with Fourier Formulas

Hello, thanks for reading my post first of all, i have a upcomming exame in calculus and i need to solve some Fourier exercices as i was trying to study for the exame i noticed that my teacher gave me a bunch of different Formulas on solving Fourier exercices and i cant wrap my head around wich one of them to use...i uploaded a picture with the Formulas that he gave me and some exercices that i need to solve. Could someone please tell me wich one of them to use? Thanks Alot!