document.write( "Question 303172: * Find the solution to this system of equations, algebraically and graphically.
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Algebra.Com's Answer #217314 by Edwin McCravy(20056)\"\" \"About 
You can put this solution on YOUR website!
* Find the solution to this system of equations, algebraically and graphically.
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document.write( "First we draw the graph of the hyperbola\r\n" );
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document.write( "\"x%5E2-2y%5E2=16\"\r\n" );
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document.write( "We put it in standard form by getting a 1 on the right\r\n" );
document.write( "by dividing every term by 16:\r\n" );
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document.write( "\"x%5E2%2F16-y%5E2%2F8=1\"\r\n" );
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document.write( "Then we find the semi-transverse and semi-conjugate axes \r\n" );
document.write( "and draw the defining rectangle, draw the asymptotes and \r\n" );
document.write( "sketch the hyperbola:\r\n" );
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document.write( "We do the same with the ellipse   x^2+4y^2=16:\r\n" );
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document.write( "\"x%5E2%2F16%2By%5E2%2F4=1\"\r\n" );
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document.write( "Then we find the semi-major and semi-minor axes and sketch \r\n" );
document.write( "the hyperbola:\r\n" );
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document.write( "That gives us this graph (in green).  I'll erase the \r\n" );
document.write( "guidelines for the hyperbola and just leave the hyperbola\r\n" );
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document.write( "So we see that the only points the red hyperbola and the green\r\n" );
document.write( "ellipse have in common are the points\r\n" );
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document.write( "(x,y) = (4,0) and (x,y) = (-4,0)\r\n" );
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document.write( "So when we do the problem algebraically we should get the\r\n" );
document.write( "values of x as 4 and -4 and the value of y as 0.\r\n" );
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document.write( "\"system%28x%5E2-2y%5E2=16%2C%0D%0A++x%5E2%2B4y%5E2=16%29\"\r\n" );
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document.write( "Solve the first equation for \"x%5E2\":\r\n" );
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document.write( "\"x%5E2=16%2B2y%5E2\".  Substitute \"%2816%2B2y%5E2%29\" for \"x%5E2\"\r\n" );
document.write( "in the second:\r\n" );
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document.write( "\"%2816%2B2y%5E2%29%2B4y%5E2=16\"\r\n" );
document.write( "\"16%2B2y%5E2%2B4y%5E2=16\"\r\n" );
document.write( "\"16%2B6y%5E2=16\"\r\n" );
document.write( "\"6y%5E2=0\"\r\n" );
document.write( "\"y%5E2=0\"\r\n" );
document.write( "\"y=0\"\r\n" );
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document.write( "Substitute 0 for y in\r\n" );
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document.write( "\"x%5E2=16%2B2y%5E2\"\r\n" );
document.write( "\"x%5E2=16%2B2%280%29%5E2\"\r\n" );
document.write( "\"x%5E2=16%2B2%280%29\"\r\n" );
document.write( "\"x%5E2=16%2B0\"\r\n" );
document.write( "\"x%5E2=16\"\r\n" );
document.write( "\"x=%22%22\"±\"4\".\r\n" );
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document.write( "So we do get for the solutions the same\r\n" );
document.write( "values algebraically as we saw that the points \r\n" );
document.write( "which the hyperbola and the ellipse had in common\r\n" );
document.write( "graphically. \r\n" );
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document.write( "(x,y) = (±4,0) or the points: \r\n" );
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document.write( "(x,y) = (4,0) and (x,y) = (-4,0)        \r\n" );
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\n" ); document.write( "* Graph the solution set of this system of inequalities:\r
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document.write( "Notice that the first is just like the equation for the green\r\n" );
document.write( "ellipse in the preceding problem except that it has\r\n" );
document.write( "an \"%22%22%3C=%22%22\" symbol instead of an equal sign \"%22%22=%22%22\".\r\n" );
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document.write( "That is the region on and inside the green ellipse with the\r\n" );
document.write( "equation \"x%5E2%2F16+%2B+y%5E2%2F4=1\".  We draw the ellipse solid \r\n" );
document.write( "not dotted because the inequality is \"%22%22%3C=%22%22\" and not \r\n" );
document.write( "\"%22%22%3C%22%22\", and thus the ellipse itself is included in the\r\n" );
document.write( "graph:\r\n" );
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document.write( "Next we see the inequality \"y%3E%281%2F2%29x-2\".  We draw the\r\n" );
document.write( "boundary line dotted since the inequality is \"%22%22%3E%22%22\"\r\n" );
document.write( "and not \"%22%22%3E=%22%22\" and therefore the graph is only\r\n" );
document.write( "the area above the line and does not include the line.\r\n" );
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document.write( "So I will erase all the part that is not to be shaded and we have\r\n" );
document.write( "just the inside area. I can't shade on here, but you can on your \r\n" );
document.write( "paper.  \r\n" );
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document.write( "Edwin
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