document.write( "Question 197025: If x^(2)+1/x^(2)=4, then what does x^(3)+1/x^(3) equal? \n" ); document.write( "
Algebra.Com's Answer #147730 by RAY100(1637)\"\" \"About 
You can put this solution on YOUR website!
x^2 +1/x^2 = 4
\n" ); document.write( ".
\n" ); document.write( "(x^4 +1) / x^2 =4
\n" ); document.write( ".
\n" ); document.write( "x^4 +1 =4x^2
\n" ); document.write( ".
\n" ); document.write( "x^4 -4x^2 +1 =0
\n" ); document.write( ".
\n" ); document.write( "Let y=x^2
\n" ); document.write( ".
\n" ); document.write( "y^2 -4y +1 =0
\n" ); document.write( ".
\n" ); document.write( "using quadratic eqn
\n" ); document.write( ".
\n" ); document.write( "y = { -(-4) +/- sqrt (16-4)} / 2
\n" ); document.write( ".
\n" ); document.write( "y = 2 +/- sqrt3
\n" ); document.write( ".
\n" ); document.write( "but y=x^2
\n" ); document.write( ".
\n" ); document.write( "x^2 =2+/- sqrt3 =2+/- 1.732 = 3.732, .268
\n" ); document.write( ".
\n" ); document.write( "x= 1.932, .518
\n" ); document.write( ".
\n" ); document.write( "Returning to x^3 + 1/x^3 = ?
\n" ); document.write( ".
\n" ); document.write( "1.932 ^3 + 1/ 1.932^3 = 7.35
\n" ); document.write( ".
\n" ); document.write( "using .518 gives same answer
\n" ); document.write( "
\n" );