document.write( "Question 1027271: [f(x)]^4 = (x + f(x))^3 and f(1)=2.
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Algebra.Com's Answer #642610 by Fombitz(32388)\"\" \"About 
You can put this solution on YOUR website!

\n" ); document.write( "I'm going to use y to simplify,
\n" ); document.write( "\"y%5E4=x%5E3%2B3x%5E2y%2B3xy%5E2%2By%5E3\"
\n" ); document.write( "Implicitly differentiating,
\n" ); document.write( "\"4y%5E3dy=3x%5E2dx%2B3%28x%5E2dy%2B2xydx%29%2B3%28y%5E2dx%2B2xydy%29%2B3y%5E2dy\"
\n" ); document.write( "\"4y%5E3dy-3y%5E2dy-3x%5E2dy-6xydy%29=3x%5E2dx%2B6xydx%2B3y%5E2dx\"
\n" ); document.write( "\"%284y%5E3-3y%5E2-6xy-3y%5E2%29dy=3%28x%5E2%2B2xy%2By%5E2%29dx\"
\n" ); document.write( "\"%284y%5E3-3y%5E2-6xy-3y%5E2%29dy=3%28x%2By%29%5E2dx\"
\n" ); document.write( "\"dy%2Fdx=%283%28x%2By%29%5E2%29%2F%284y%5E3-3y%5E2-6xy-3y%5E2%29\"
\n" ); document.write( "However, it's not the case that \"f%281%29=2\" because,
\n" ); document.write( "\"%282%29%5E4=%281%2B2%29%5E3\"
\n" ); document.write( "\"16=%283%29%5E3\"
\n" ); document.write( "\"16%3C%3E27\"
\n" ); document.write( "Actually,
\n" ); document.write( "\"y%5E4=%281%2By%29%5E3\"
\n" ); document.write( "has two real solutions,
\n" ); document.write( "\"y=-0.55\" and \"y=2.63\"
\n" ); document.write( "which yields two values for the derivatives,
\n" ); document.write( "\"dy%2Fdx=-0.480\" and \"dy%2Fdx=1.189\"
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\n" ); document.write( "Here is the function along with the two tangent lines at \"x=1\"
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