document.write( "Question 117751: 2, 6 , 18 , 54 , ....
\n" ); document.write( " In the sequence above what would be the 8th term?
\n" ); document.write( "

Algebra.Com's Answer #85721 by jim_thompson5910(35256)\"\" \"About 
You can put this solution on YOUR website!
Notice that each term is increasing quickly. So this sequence might be a geometric sequence. To find out, let's simply divide the terms.\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "First divide the 2nd term 6 by the 1st term 2 to get \r
\n" ); document.write( "\n" ); document.write( "\"6%2F2=3\" \r
\n" ); document.write( "\n" ); document.write( "
\n" ); document.write( "Now divide the 3rd term 18 by the 2nd term 6 to get \r
\n" ); document.write( "\n" ); document.write( "\"18%2F6=3\" \r
\n" ); document.write( "\n" ); document.write( "
\n" ); document.write( "Now divide the 4th term 54 by the 3rd term 18 to get \r
\n" ); document.write( "\n" ); document.write( "\"54%2F18=3\" \r
\n" ); document.write( "\n" ); document.write( " \r
\n" ); document.write( "\n" ); document.write( "So if we pick any term and divide it by the previous term, we'll always get 3. This is the common ratio between the terms. So this means that \"r=3\".\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Now since we've started at 2, this means that \"a=2\"\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Since the general geometric sequence is \"a%5Bn%5D=ar%5En\", this means the sequence is\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"a%5Bn%5D=2%2A3%5En\"\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Notice if we let n=0, we get\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "
\n" ); document.write( "\"a%5B0%5D=2%2A3%5E0=2%2A1=2\" notice this is the first term\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "and if we let n=1, we get\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"a%5B1%5D=2%2A3%5E1=2%2A3=6\" notice this is the second term\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "and this generates the sequence 2, 6 , 18 , 54 , ....\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "So to find the 8th term, let n=7 (remember, we started at n=0)\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"a%5B7%5D=2%2A3%5E7=2%2A2187=4374\" Plug in n=7 and simplify\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "So the eighth term is 4,374
\n" ); document.write( "
\n" ); document.write( "
\n" );