document.write( "Question 88435: Hello, I am having diffuclties understanding this problem. \r
\n" ); document.write( "\n" ); document.write( "Find all real and imaginary zeros for each polynomial factor.
\n" ); document.write( "f(x) = 2x^2-1=0\r
\n" ); document.write( "\n" ); document.write( "Here is the work that I have started with but I am unsure if I am doing this properly\r
\n" ); document.write( "\n" ); document.write( "2x^2-1=0
\n" ); document.write( "+1 = +1
\n" ); document.write( "2x^2=1
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\n" ); document.write( "2\r
\n" ); document.write( "\n" ); document.write( "x^2=1/2\r
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\n" ); document.write( "\n" ); document.write( "would my answer be x= square root of +1/2 and square root of -1/2? \r
\n" ); document.write( "\n" ); document.write( "Thank you for your help
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Algebra.Com's Answer #64283 by jim_thompson5910(35256)\"\" \"About 
You can put this solution on YOUR website!
Now let's use the quadratic formula to solve for x:\r
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\n" ); document.write( "\n" ); document.write( "Starting with the general quadratic\r
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\n" ); document.write( "\n" ); document.write( "\"ax%5E2%2Bbx%2Bc=0\"\r
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\n" ); document.write( "\n" ); document.write( "the general solution using the quadratic equation is:\r
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\n" ); document.write( "\n" ); document.write( "\"x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29\"\r
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\n" ); document.write( "\n" ); document.write( "So lets solve \"2%2Ax%5E2-1=0\" (note: since the polynomial does not have an \"x\" term, the 2nd coefficient is zero. In other words, b=0. So that means the polynomial really looks like \"2%2Ax%5E2%2B0%2Ax-1=0\" notice \"a=2\", \"b=0\", and \"c=-1\")\r
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\n" ); document.write( "\n" ); document.write( "\"x+=+%28-0+%2B-+sqrt%28+%280%29%5E2-4%2A2%2A-1+%29%29%2F%282%2A2%29\" Plug in a=2, b=0, and c=-1\r
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\n" ); document.write( "\n" ); document.write( "\"x+=+%28-0+%2B-+sqrt%28+0-4%2A2%2A-1+%29%29%2F%282%2A2%29\" Square 0 to get 0\r
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\n" ); document.write( "\n" ); document.write( "\"x+=+%28-0+%2B-+sqrt%28+0%2B8+%29%29%2F%282%2A2%29\" Multiply \"-4%2A-1%2A2\" to get \"8\"\r
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\n" ); document.write( "\n" ); document.write( "\"x+=+%28-0+%2B-+sqrt%28+8+%29%29%2F%282%2A2%29\" Combine like terms in the radicand (everything under the square root)\r
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\n" ); document.write( "\n" ); document.write( "\"x+=+%28-0+%2B-+2%2Asqrt%282%29%29%2F%282%2A2%29\" Simplify the square root\r
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\n" ); document.write( "\n" ); document.write( "\"x+=+%28-0+%2B-+2%2Asqrt%282%29%29%2F4\" Multiply 2 and 2 to get 4\r
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\n" ); document.write( "\n" ); document.write( "So now the expression breaks down into two parts\r
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\n" ); document.write( "\n" ); document.write( "\"x+=+%28-0+%2B+2%2Asqrt%282%29%29%2F4\" or \"x+=+%28-0+-+2%2Asqrt%282%29%29%2F4\"\r
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\n" ); document.write( "\n" ); document.write( "Which simplifies to \r
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\n" ); document.write( "\n" ); document.write( "\"x+=+sqrt%282%29%2F2\" or \"x+=+-+sqrt%282%29%2F2\"\r
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\n" ); document.write( "\n" ); document.write( "So the roots approximate to\r
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\n" ); document.write( "\n" ); document.write( "\"x=0.707106781186548\" or \"x=-0.707106781186548\"\r
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\n" ); document.write( "\n" ); document.write( "So our solutions are:\r
\n" ); document.write( "\n" ); document.write( "\"x=0.707106781186548\" or \"x=-0.707106781186548\"\r
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\n" ); document.write( "\n" ); document.write( "Notice when we graph \"2%2Ax%5E2-1\", we get:\r
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\n" ); document.write( "\n" ); document.write( "when we use the root finder feature on a calculator, we find that \"x=0.707106781186548\" and \"x=-0.707106781186548\".So this verifies our answer\r
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\n" ); document.write( "\n" ); document.write( "note:\r
\n" ); document.write( "\n" ); document.write( "Since \"0%2B-sqrt%282%29%2F2=0%2B-sqrt%281%2F2%29\" this means you were really close. You just need to make sure that the negative is placed on the outside of the square root.
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