document.write( "Question 1090885: Can someone help me?
\n" ); document.write( "A sequence {g n} is defined recursively as g 1=72, g n=-2/3*g n-1 , for n ≥2\r
\n" ); document.write( "\n" ); document.write( "(note: here \"n\" & \"1\"& \"n-1\" after \"g\" should be a smaller letter, I cannot put it here as smaller)\r
\n" ); document.write( "\n" ); document.write( "a. Determine the values of g 2, g 3, and g 4
\n" ); document.write( "b. Write an explicit formula for g n
\n" ); document.write( "Thank you.
\n" ); document.write( "

Algebra.Com's Answer #705333 by KMST(5328)\"\" \"About 
You can put this solution on YOUR website!
I believe you meant \"g%5B1%5D=72\" and \"g%5Bn%5D=-%282%2F3%29%2Ag%5Bn-1%5D\" .\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "a) \"system%28g%5Bn%5D=-%282%2F3%29%2Ag%5Bn-1%5D%2Cg%5B1%5D=72%29\" -->
\n" ); document.write( "\"g%5B2%5D=-%282%2F3%29%2A72\"
\n" ); document.write( "\"g%5B2%5D=-2%2A72%2F3\"
\n" ); document.write( "\"highlight%28g%5B2%5D=-48%29\"
\n" ); document.write( "\"g%5B3%5D=-%282%2F3%29%2A%28-48%29\"
\n" ); document.write( "\"g%5B3%5D=2%2A48%2F3\"
\n" ); document.write( "\"highlight%28g%5B3%5D=32%29\"
\n" ); document.write( "\"g%5B4%5D=-%282%2F3%29%2A32\"
\n" ); document.write( "\"g%5B4%5D=-2%2A32%2F3\"
\n" ); document.write( "\"highlight%28g%5B4%5D=-64%2F3%29\"
\n" ); document.write( "
\n" ); document.write( "b) \"g%5Bn%5D=g%5B1%5D%2Ar%5E%28n-1%29\" is the general explicit formula for a geometric sequence with first term \"g%5B1%5D\" and common ratio \"r\" .
\n" ); document.write( "For the sequence in this problem,
\n" ); document.write( "\"highlight%28g%5Bn%5D=72%2A%28-2%2F3%29%5E%28n-1%29%29\" ,
\n" ); document.write( "That is \"an explicit formula\" for \"g%5Bn%5D\" .
\n" ); document.write( "As \"72=8%2A9=2%5E3%2A3%5E2\" , the formula could be \"simplified\"
\n" ); document.write( "\"g%5Bn%5D=72%2A%28-2%2F3%29%5E%28n-1%29\"
\n" ); document.write( "\"g%5Bn%5D=2%5E3%2A3%5E2%2A%28-1%29%5E%28n-1%29%2A2%5E%28n-1%29%2F3%5E%28n-1%29\"
\n" ); document.write( "\"highlight%28g%5Bn%5D=%28-1%29%5E%28n-1%29%2A2%5E%28n%2B2%29%2F3%5E%28n-3%29%29\"
\n" ); document.write( "That last equation is also \"an explicit formula\" for \"g%5Bn%5D\" .
\n" ); document.write( "As a formula it may not look simple,
\n" ); document.write( "but it would help if you had to calculate several terms,
\n" ); document.write( "because it would simplify calculations like
\n" ); document.write( "\"g%5B4%5D=%28-1%29%5E3%2A2%5E6%2F3%5E1=-64%2F3\" , and
\n" ); document.write( "\"g%5B7%5D=%28-1%29%5E6%2A2%5E9%2F3%5E4=512%2F81\" .
\n" ); document.write( "
\n" );