document.write( "Question 868395: For the sequence 2, 9, 28, 65,... How do I find the next term and the rule for the nth term \n" ); document.write( "
Algebra.Com's Answer #523515 by jim_thompson5910(35256)\"\" \"About 
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Subtract 1 from each term to get \r
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\n" ); document.write( "\n" ); document.write( "2-1 = 1
\n" ); document.write( "9-1 = 8
\n" ); document.write( "28-1 = 27
\n" ); document.write( "65-1 = 64\r
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\n" ); document.write( "\n" ); document.write( "Each number on the right hand side (RHS) is a perfect cube\r
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\n" ); document.write( "\n" ); document.write( "1 = 1^3
\n" ); document.write( "8 = 2^3
\n" ); document.write( "27 = 3^3
\n" ); document.write( "64 = 4^3\r
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\n" ); document.write( "\n" ); document.write( "So the rule is \"cube the number, then add 1\". We add 1 to undo the subtraction of 1 we did in the first part (see above)\r
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\n" ); document.write( "\n" ); document.write( "So the rule is \"highlight%28n%5E3+%2B+1%29\" where n is a positive whole number.\r
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\n" ); document.write( "\n" ); document.write( "Once you get the general rule or formula, it's always a good idea to test it with the given sequence you already have. For instance, the third term is given to be 28. So if we did things right, then plugging n = 3 into the formula should give 28. Since \"n%5E3+%2B+1+=+3%5E3+%2B+1+=+27+%2B+1+=+28\", this example confirms it. I recommend testing the other remaining terms.\r
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\n" ); document.write( "\n" ); document.write( "The next term would be when \"n+=+5\", so the next term is \"n%5E3+%2B+1+=+5%5E3+%2B+1+=+125+%2B+1+=+highlight%28126%29\"\r
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\n" ); document.write( "\n" ); document.write( "Note: you can do each part in any order, but I find it easier to find the general rule/formula first.
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