document.write( "Question 1014011: What is the formula for the sequence 5,5,35,65,275. . . \n" ); document.write( "
Algebra.Com's Answer #630369 by Edwin McCravy(20066)\"\" \"About 
You can put this solution on YOUR website!

\n" ); document.write( "First we'll try a sum of nth powers with the first two terms:
\n" ); document.write( "If that doesn't work, we'll try the difference of nth powers \r
\n" ); document.write( "\n" ); document.write( "\"a%5Bn%5D\"\"%22%22=%22%22\"\"x%5En%2By%5En\"\r
\n" ); document.write( "\n" ); document.write( "\"5\"\"%22%22=%22%22\"\"x%5E1%2By%5E1\"
\n" ); document.write( "\"5\"\"%22%22=%22%22\"\"x%5E2%2By%5E2\"\r
\n" ); document.write( "\n" ); document.write( "\"system%28x%2By=5%2Cx%5E2%2By%5E2=5%29\"\r
\n" ); document.write( "\n" ); document.write( "\r
\n" ); document.write( "\n" ); document.write( "No good. Comes out with imaginary values for x and y\r
\n" ); document.write( "\n" ); document.write( "So we try a difference of powers for the first two terms:\r
\n" ); document.write( "\n" ); document.write( "\"a%5Bn%5D\"\"%22%22=%22%22\"\"x%5En-y%5En\"\r
\n" ); document.write( "\n" ); document.write( "\"5\"\"%22%22=%22%22\"\"x%5E1-y%5E1\"
\n" ); document.write( "\"5\"\"%22%22=%22%22\"\"x%5E2-y%5E2\"\r
\n" ); document.write( "\n" ); document.write( "\"system%28x-y=5%2Cx%5E2-y%5E2=5%29\"\r
\n" ); document.write( "\n" ); document.write( "\r
\n" ); document.write( "\n" ); document.write( "\"matrix%283%2C1%2C%0D%0Ax-5=y%2C%0D%0A3-5=y%2C%0D%0A-2=y%29\"\r
\n" ); document.write( "\n" ); document.write( "So the formula we get from the first two terms,
\n" ); document.write( "substituting x=3 and y=-2 in\r
\n" ); document.write( "\n" ); document.write( "\"a%5Bn%5D\"\"%22%22=%22%22\"\"x%5En-y%5En\"\r
\n" ); document.write( "\n" ); document.write( "becomes\r
\n" ); document.write( "\n" ); document.write( "\"a%5Bn%5D\"\"%22%22=%22%22\"\"3%5En-%28-2%29%5En\"\r
\n" ); document.write( "\n" ); document.write( "But we must check to see if it holds for all the given
\n" ); document.write( "numbers in the series:\r
\n" ); document.write( "\n" ); document.write( "\"a%5B1%5D\"\"%22%22=%22%22\"\"3%5E1-%28-2%29%5E1\"\"%22%22=%22%22\"\"3-%28-2%29\"\"%22%22=%22%22\"\"3%2B2\"\"%22%22=%22%22\"\"5\"\r
\n" ); document.write( "\n" ); document.write( "\"a%5B2%5D\"\"%22%22=%22%22\"\"3%5E2-%28-2%29%5E2\"\"%22%22=%22%22\"\"9-%284%29\"\"%22%22=%22%22\"\"5\"\r
\n" ); document.write( "\n" ); document.write( "\"a%5B3%5D\"\"%22%22=%22%22\"\"3%5E3-%28-2%29%5E3\"\"%22%22=%22%22\"\"27-%28-8%29\"\"%22%22=%22%22\"\"27%2B8\"\"%22%22=%22%22\"\"35\"\r
\n" ); document.write( "\n" ); document.write( "\"a%5B4%5D\"\"%22%22=%22%22\"\"3%5E4-%28-2%29%5E4\"\"%22%22=%22%22\"\"81-%2816%29\"\"%22%22=%22%22\"\"65\"\r
\n" ); document.write( "\n" ); document.write( "\"a%5B5%5D\"\"%22%22=%22%22\"\"3%5E5-%28-2%29%5E5\"\"%22%22=%22%22\"\"243-%28-32%29\"\"%22%22=%22%22\"\"243%2B32\"\"%22%22=%22%22\"\"275\"\r
\n" ); document.write( "\n" ); document.write( "So it works for all the given terms, so the formula is:\r
\n" ); document.write( "\n" ); document.write( "\"a%5Bn%5D\"\"%22%22=%22%22\"\"3%5En-%28-2%29%5En\"\r
\n" ); document.write( "\n" ); document.write( "Edwin
\n" ); document.write( "
\n" );