document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=989715>Question 989715</A>: <I><SPAN STYLE=\"word-break: break-all;\"> The total cost of repaying a student loan at an interest rate of r% per year is C=f(r),\r<BR>\n" );
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document.write( "a) What is the meaning of the derivative f(r)? What are its units? <BR>\n" );
document.write( "b) What does the statement f'(10)=1200 mean?<BR>\n" );
document.write( "c)Is f(r) always positive or does it change sign? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #609953 by </B><A HREF=/tutors/aboutme.mpl?userid=Timnewman><B>Timnewman(323)</B></A><img src=\"/images/stars/stars-10.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Timnewman><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=Timnewman><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=609953\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> a.It means that Cost is a function of r in percent and since it involves money,it's unit depends on the contry to which it is being used.e.g if used in USA,the unit is dollar($).if used in Nigeria,the unit is naira(#).etc.<BR>\n" );
document.write( "2.The statement f'(10)=1200<BR>\n" );
document.write( "means that when the function is differentiated and 10 is logged into the drivative then the result will be 1200.<BR>\n" );
document.write( "3.Since it involves money,The sign is always positive not nagative.even if there is nagative answer,take the modulus so as to get positive value. </SPAN>\n" );
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