document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1156187>Question 1156187</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Please help me with this related rates question<BR>\n" );
document.write( "if two resistors with resistances R1 and R2 are connected in parallel, as in the figure below, then the total resistance R, measured in ohms (Ω), is given by<BR>\n" );
document.write( "1/R = 1/R1+1/R2\r<BR>\n" );
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document.write( "If R1 and R2 are increasing at rates of 0.3 Ω/s and 0.2 Ω/s, respectively, how fast is R changing when R1 = 80 Ω and R2 = 100 Ω? (Round your answer to three decimal places.) </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #778866 by </B><A HREF=/tutors/aboutme.mpl?userid=Boreal><B>Boreal(15235)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Boreal><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=Boreal><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=778866\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> 1/R=1/80+1/100; multiply by LCD of 400R and 400=5R+4R=9R, so R=400/9=44.44 ohms\r<BR>\n" );
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document.write( "R^(-1)=(R1)^(-1)+R2^(-1)<BR>\n" );
document.write( "-1/R^2 dR/ds=-1/R1^2 dR1/ds-1/R2^2 dR2/ds<BR>\n" );
document.write( "-1/1975.31 dR/ds=-1/6400*0.3-1/10000*0.2<BR>\n" );
document.write( "so <BR>\n" );
document.write( "-0.000506 dR/ds=-0.0000469-0.00002=-0.0000669.  Change all signs and divide by 0.000506<BR>\n" );
document.write( "dR/ds=0.132 ohms/sec. </SPAN>\n" );
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