document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=330494>Question 330494</A>: <I><SPAN STYLE=\"word-break: break-all;\"> please find the equation of the tangent to the curve given by<BR>\n" );
document.write( "y= x^3 - 5x + 15<BR>\n" );
document.write( "at the point where x= -1<BR>\n" );
document.write( "I got the answer to be<BR>\n" );
document.write( "y= -2x +17<BR>\n" );
document.write( "but im not sure if this is right.<BR>\n" );
document.write( "could you show working if im incorrect please.thanks </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #236894 by </B><A HREF=/tutors/aboutme.mpl?userid=Jk22><B>Jk22(389)</B></A><img src=\"/images/stars/stars-10.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Jk22><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=Jk22><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=236894\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Q : tangent to the curve given by<BR>\n" );
document.write( "y= x^3 - 5x + 15<BR>\n" );
document.write( "at the point where x= -1 ? \r<BR>\n" );
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document.write( "y(-1)=-1+5+15=19<BR>\n" );
document.write( "y'(x)=3*x^2-5, y'(-1)=3-5=-2\r<BR>\n" );
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document.write( "let ytan(x)=ax+b\r<BR>\n" );
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document.write( "ytan(-1)=-a+b=19<BR>\n" );
document.write( "ytan'(-1)=a=-2   => b=19+a=17\r<BR>\n" );
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document.write( "hence ytan(x)=-2x+17 </SPAN>\n" );
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