arithmetic progression
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pka
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- Jan 29, 2005
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Welcome to this forum. When posting please show some of your own work.
Then tell us with what part you need help.
This will get you started: \(\displaystyle a_n=a_1+(n-1)d\) gives the terms.
From the given, you need to find \(\displaystyle a_1~\&~d\).
I am convinced that you know that an arithmetic progression is defined by a, (a + d), (a + 2d), (a + 3d), etc. where a = the first term and d = the common difference.
Similarly, I am certain that you know that the nth term of an arithmetic progression, N, is defined by N = a + (n - 1)d
You have been told that the sum of the first three terms of an arithmetic progression is 12 and the twentieth term is -32.
Now, where do your given pieces of information fit into these expressions for arithmetic progressions?
Similarly, I am certain that you know that the nth term of an arithmetic progression, N, is defined by N = a + (n - 1)d
You have been told that the sum of the first three terms of an arithmetic progression is 12 and the twentieth term is -32.
Now, where do your given pieces of information fit into these expressions for arithmetic progressions?