document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=63561>Question 63561</A>: <I><SPAN STYLE=\"word-break: break-all;\"> I need help on this homework problem. Thank you for any help you can provide.\r<BR>\n" );
document.write( "\n" );
document.write( "a1=1 r=-1 find s20\r<BR>\n" );
document.write( "\n" );
document.write( "I keep getting 1 as the answer but the answer is 0. what am I missing? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #44277 by </B><A HREF=/tutors/aboutme.mpl?userid=stanbon><B>stanbon(75887)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=stanbon><IMG SRC=http://www.algebra.com/images/aboutme-small.gif BORDER=0 alt=\"About Me\" VALIGN=MIDDLE></A>&nbsp;<IMG SRC=http://www.algebra.com/images/nopicture.jpg><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=44277\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> a1=1 r=-1 find s20<BR>\n" );
document.write( "---------<BR>\n" );
document.write( "S(n)= a(1)[r^(n+1)-1]/ [r-1]<BR>\n" );
document.write( "S(20)= 1[[(-1)^(21)-1]/[-1-1]<BR>\n" );
document.write( "S(20)= [-1-1]/[-1-1]=1<BR>\n" );
document.write( "You are correct.<BR>\n" );
document.write( "Cheers,<BR>\n" );
document.write( "Stan H. </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );