But I think as long as you study hard, there is no problem. You should know the general formula of arithmetic progression and geometric progression, the summation formula of the first n terms, and how to get the most basic sequence knowledge of arithmetic progression's general formula and summation formula, and then do some corresponding questions to master the foundation.
Also, you can ask the teacher more questions! Because you have more ideas to contact the teacher, you will learn when you hear the teacher's problem-solving ideas!
Remember!
Wish you success!