document.write( "Question 1184166: Solve algebraic expression \"+a%5E6+-12a%5E4+%2B+48a%5E2+-+61+=+0+\" and find the real roots. \n" ); document.write( "
Algebra.Com's Answer #814696 by greenestamps(13200)\"\" \"About 
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\n" ); document.write( "\"+f%28a%29+=+a%5E6+-12a%5E4+%2B+48a%5E2+-+61+\"

\n" ); document.write( "Graphing the function will help us see if our results are reasonable. Here is a graph:

\n" ); document.write( "\"graph%28400%2C400%2C-3%2C3%2C-20%2C20%2Cx%5E6-12x%5E4%2B48x%5E2-61%29\"

\n" ); document.write( "Note the graph is even (symmetrical with respect to the y-axis, because every exponent in the polynomial is even.

\n" ); document.write( "There is no general method for solving a 6th degree polynomial equation.

\n" ); document.write( "By far the easiest way to find the APPROXIMATE real roots is by graphing the function on a graphing calculator and finding the zeros from the graph.

\n" ); document.write( "My TI-83 shows the real roots to be +/- 1.599296855 to 9 decimal places, which is consistent with the graph.

\n" ); document.write( "You can get that same result using Newton's Method. Look on the internet for a video on how to use Newton's Method on a TI83 or TI84 calculator.

\n" ); document.write( "I would consider doing that very worthwhile, since Newton's Method is a very powerful tool.

\n" ); document.write( "Finally, there is a way to find the exact real roots for this example.

\n" ); document.write( "Since the function is even, let y=a^2 and write the equation as

\n" ); document.write( "x^3-12x^2+48x-61=0

\n" ); document.write( "Then look again on the internet and find the formula for the general solution of a cubic equation and use it; then remember that you are solving for a=sqrt(x), not for x.

\n" ); document.write( "It is a very ugly formula, which I have never tried to use; and I have no inclination to try it on your example. So if you want to find the exact real zeros, I say have fun...!

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