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1. First step: substitute n = 0 to the formula and calculate.
2. Second step: substitute n = 1 to the formula and calculate.
Do the next steps in the same way.
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I really don't like when the students (the students ???????) come with such questions.
It must be absolutely clear for them what to do after reading this text.
There is no need to disturb the tutors with such questions.
Good luck !!
I wish you to get a full susses in completing this assignment on your own after my instructions and explanations.