Question

Which of the following is the general term for the sequence m, -m, m, -m, . . .?

Answer 1

Answer:

  A. m(-1)^(n-1)

Step-by-step explanation:

The degree of m doesn't change so none of the expressions with n as an exponent of m can possibly be correct. That leaves only choice A.

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You will find that when alternating signs are required, the term (-1)^n will be a factor. An offset of ±1 can be added to the n to make the initial sign be what you want. Here we want +1 for n=1, so an exponent of (n-1) is appropriate.