document.write( "Question 192853: Please help me to solve this polynomial:\r
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document.write( "f(x)=(x-8)(x+3)(x-9)(x+8)(x-2)(x+5)(x-2)\r
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document.write( "I have to write ALL the process down. I tried it and got a result, but when I graph it, it was different to my original function.\r
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document.write( "Thanks! \n" );
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Algebra.Com's Answer #144777 by RAY100(1637)![]() ![]() ![]() You can put this solution on YOUR website! This is an interesting problem, if only from its size.\r \n" ); document.write( "\n" ); document.write( "we started by arranging the factors in order. \r \n" ); document.write( "\n" ); document.write( "y=(x-9)(x-8)(x-2)(x-2)(x-3)(x-5)(x-8)\r \n" ); document.write( "\n" ); document.write( "note this is a 7th degree function. This means(7 roots) and it is an odd function\r \n" ); document.write( "\n" ); document.write( "we can find the roots from the factors, for example set x-9=0, x=-9 root likewise the roots in order are, 9,8,2,2,3,5,8.\r \n" ); document.write( "\n" ); document.write( "Note that the root (2) happens twice, this means the function curve just touches the y=0 axis but does not pass thru. With the other roots the function intersects and passes thru.\r \n" ); document.write( "\n" ); document.write( "note it is a positive function. If we look close the leading coefficient will be plus, because we have no negative (x) in factors. After we multiply all factors, this holds true.\r \n" ); document.write( "\n" ); document.write( "Summarizing, it is a positive odd function, with 7 roots, and these roots are defined by the factors. \r \n" ); document.write( "\n" ); document.write( "The odd positive nature indicates as we graph the function starts at the left with a negative and moves upward to positive right. \r \n" ); document.write( "\n" ); document.write( "If we use a standard x - y coordinate system and make just a rough sketch, we can define the shape of the function.\r \n" ); document.write( "\n" ); document.write( "starting at lower left we rise thru x=(-8), turn and pass downward thru x=(-5) turn and pass upward thru (x=-3), turn downward and just touch the axis at x=(+2) before turning upward and then downward thru x=(8),and then turn and pass upward thru x=(9) and continuing upwards. \r \n" ); document.write( "\n" ); document.write( "We see 6 turns which is consistent with a 7 degree function\r \n" ); document.write( "\n" ); document.write( "We would probably say the problem is complete here, but you seemed to want to expand the function. This is a lot of work and many chances for numerical error. \r \n" ); document.write( "\n" ); document.write( "I started with a clean sheet of paper sideways.\r \n" ); document.write( "\n" ); document.write( "i did 2 factor by themselves, as this allowed the use of foil\r \n" ); document.write( "\n" ); document.write( "1)(x+8)(x-8)= x^2-64 \n" ); document.write( "2)(x-2)(x-2)=x^2-4x-4 \n" ); document.write( "3)(x+3)(x-7)=x^2 -4x-21 \n" ); document.write( "4)(x-5) had no mate\r \n" ); document.write( "\n" ); document.write( "now we multiplied 1*2 and 3*4\r \n" ); document.write( "\n" ); document.write( "5) x^4-4x^3-60x^2+256x-256 \n" ); document.write( "6)x^3-x^2-57x-135\r \n" ); document.write( "\n" ); document.write( "and lastly we multiplied 5*6 \n" ); document.write( "but we set each distribution on a horizontal line and matched the next distribution below. \n" ); document.write( "This resulted in a vertical accounting of the for factors, one vertical column for each degree.\r \n" ); document.write( "\n" ); document.write( "The result was \n" ); document.write( "y=x^7-5x^6-113x^5+409x^4+3960x^3+9303x^2-19968x+34560\r \n" ); document.write( "\n" ); document.write( "my graphing calc did not like this but i feel the above sketch is correct.\r \n" ); document.write( "\n" ); document.write( "to recheck, i would wait a day and redo\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " |