document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=388620>Question 388620</A>: <I><SPAN STYLE=\"word-break: break-all;\"> 4 A recurrance relationship is such that Un+1=a/4Un+12. <BR>\n" );
document.write( "4(a).If U0=16 show clearly that U2=aČ+3a+12 <BR>\n" );
document.write( "4(b).Hence find a if U2=30 and a>0\r<BR>\n" );
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document.write( "Can you provide full working with solution.\r<BR>\n" );
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document.write( "Many Thanks,<BR>\n" );
document.write( "Andy </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #275060 by </B><A HREF=/tutors/aboutme.mpl?userid=robertb><B>robertb(5830)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=robertb><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/cgi-bin/show-face.mpl?user=robertb><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=275060\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=U_%28n%2B1%29+=+%28a%2F4%29U_n+%2B+12 ALIGN=MIDDLE  ALT=\"U_%28n%2B1%29+=+%28a%2F4%29U_n+%2B+12\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "a. U_0 = 16 ===> <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=U_1+=+%28a%2F4%29%2A16+%2B+12+=+4a+%2B+12 ALIGN=MIDDLE  ALT=\"U_1+=+%28a%2F4%29%2A16+%2B+12+=+4a+%2B+12\"   DISABLED_style= \"max-width:90%; height:auto;\" >.  Then<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=U_2+=+%28a%2F4%29%2A%284a%2B12%29+%2B+12+=+a%28a%2B3%29%2B12+=+a%5E2+%2B+3a+%2B+12 ALIGN=MIDDLE  ALT=\"U_2+=+%28a%2F4%29%2A%284a%2B12%29+%2B+12+=+a%28a%2B3%29%2B12+=+a%5E2+%2B+3a+%2B+12\"   DISABLED_style= \"max-width:90%; height:auto;\" >.\r<BR>\n" );
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document.write( "b.If <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=U_2+=+30+=+a%5E2+%2B+3a+%2B+12 ALIGN=MIDDLE  ALT=\"U_2+=+30+=+a%5E2+%2B+3a+%2B+12\"   DISABLED_style= \"max-width:90%; height:auto;\" >, then <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=a%5E2+%2B+3a+-18+=+0 ALIGN=MIDDLE  ALT=\"a%5E2+%2B+3a+-18+=+0\"   DISABLED_style= \"max-width:90%; height:auto;\" >, and (a+6)(a-3) = 0.  Therefore a = 3.  (Eliminate -6 because we want a>0). </SPAN>\n" );
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