document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=243303>Question 243303</A>: <I><SPAN STYLE=\"word-break: break-all;\"> The function y=x^4+bx^2+8x+1 has a horizontal tangent and a point of inflection for the same value of x. What must be the value of b?\r<BR>\n" );
document.write( "\n" );
document.write( "(A) -6<BR>\n" );
document.write( "(B) -1<BR>\n" );
document.write( "(C) 1<BR>\n" );
document.write( "(D) 4<BR>\n" );
document.write( "(E) 6 </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #178234 by </B><A HREF=/tutors/aboutme.mpl?userid=Alan3354><B>Alan3354(69443)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Alan3354><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=Alan3354><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=178234\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> The function y=x^4+bx^2+8x+1 has a horizontal tangent and a point of inflection for the same value of x. What must be the value of b? <BR>\n" );
document.write( "(A) -6<BR>\n" );
document.write( "(B) -1<BR>\n" );
document.write( "(C) 1<BR>\n" );
document.write( "(D) 4<BR>\n" );
document.write( "(E) 6<BR>\n" );
document.write( "----------<BR>\n" );
document.write( "y' = 4x^3 + 2bx + 8 = 0 slope = 0<BR>\n" );
document.write( "y'' = 12x^2 + 2b = 0 inflection<BR>\n" );
document.write( "-----------------<BR>\n" );
document.write( "2x^3 + bx + 4 = 0<BR>\n" );
document.write( "6x^2 + b = 0<BR>\n" );
document.write( "---------------<BR>\n" );
document.write( "b = -6 (x = 1)\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );