Arithmetic progression question!
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Question: The sum, Sn, of the first n terms of a sequence is given by Sn = pn + qn², where p and q are constants. Prove that the sequence is an arithmetic progression, and hence, find the first term and common difference.
Answer for first term and common difference is p+q and 2q. No matter how I do. My answer is p and q. Anyone who can help me? -
To prove that it is an A.P, just take the n-th term and minus away the (n-1)-th term. Do the same for the (n-1)-th term and minus away the (n-2)-th term. Verify that both are the same. Of course, say that n is more than 2.
The first term just let n = 1 --> p + q
The common difference just take the answer above.
Anyway, Maths Forum over liao. Next time ask your teacher.
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Okay. Thanks! I got it already.