document.write( "Question 1114498: Find the value for c such that y = x + c is a tangent to the parabola
\n" ); document.write( "y = x^2-x-12.\r
\n" ); document.write( "\n" ); document.write( "Can you please help me do questions like that? What is meant by 'tangent to the parabola'? \r
\n" ); document.write( "\n" ); document.write( "Thankyou
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Algebra.Com's Answer #729442 by josgarithmetic(39617)\"\" \"About 
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\n" ); document.write( "What is meant by 'tangent to the parabola'?
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\n" ); document.write( "\n" ); document.write( "The line which touches but does not cross the parabola at the particular local point.\r
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\n" ); document.write( "\n" ); document.write( "\"y+=+x%5E2-x-12\"
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\n" ); document.write( "\"dx%2Fdy=2x-1\"\r
\n" ); document.write( "\n" ); document.write( "Slope of a tangent line to the parabola is \"2x-1\".\r
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\n" ); document.write( "\n" ); document.write( "\"y=mx%2Bc=%282x-1%29x%2Bc=1%2Ax%2Bc\"
\n" ); document.write( "meaning, \"2x-1=1\"
\n" ); document.write( "\"2x=2\"
\n" ); document.write( "\"x=1\"\r
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\n" ); document.write( "\n" ); document.write( "The point on the parabola for x=1 is
\n" ); document.write( "\"y=x%5E2-x-12\"
\n" ); document.write( "\"y=1-1-12\"
\n" ); document.write( "\"y=-12\"\r
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\n" ); document.write( "\n" ); document.write( "This point (1,-12) is both on the parabola and also on the line \"y=x%2Bc\".\r
\n" ); document.write( "\n" ); document.write( "\"c=y-x\"
\n" ); document.write( "\"c=-12-1\"
\n" ); document.write( "\"highlight%28c=-13%29\"\r
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\n" ); document.write( "\n" ); document.write( "The tangent line at that point:
\n" ); document.write( "\"highlight%28y=x-13%29\"\r
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\n" ); document.write( "\n" ); document.write( "\"graph%28300%2C300%2C-7%2C7%2C-13%2C1%2Cx%5E2-x-12%2Cx-13%29\"
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