document.write( "Question 206413: Hi all, I was hoping someone could show me how to solve the following,
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Algebra.Com's Answer #155970 by Edwin McCravy(20055)\"\" \"About 
You can put this solution on YOUR website!
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document.write( "I did this problem for you recently, Nick.  Here it is again.\r\n" );
document.write( "Is there something about it that you didn't understand about\r\n" );
document.write( "lines in space?  Would you understand it better if I used\r\n" );
document.write( "the i,j,k notation instead of the ‹a,b,c› notation? \r\n" );
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document.write( "If you need further help, you may email me at AnlytcPhil@aol.com\r\n" );
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document.write( "A line parallel to the vector v = ‹a,b,c› and passing through the\r\n" );
document.write( "point P(\"x%5B1%5D\",\"y%5B1%5D\",\"z%5B1%5D\") is represented by the\r\n" );
document.write( "parametric equations\r\n" );
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document.write( "\"x=x%5B1%5D%2Bat\", \"y=y%5B1%5D%2Bbt\", \"z=z%5B1%5D%2Bct\"\r\n" );
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document.write( "or as the symmetric equations:\r\n" );
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document.write( "\"%28x-x%5B1%5D%29%2Fa=%28y-y%5B1%5D%29%2Fb=%28z-z%5B1%5D%29%2Fc\"\r\n" );
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document.write( "if none of a,b, or c are 0.\r\n" );
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document.write( "Begin by using the points P(2,1,-3) and Q(-1,4,1) \r\n" );
document.write( "to find a direction vector for the line passing through \r\n" );
document.write( "P and Q, given by\r\n" );
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document.write( "v = PQ = ‹-1-(2),4-1,1-(-3)› = ‹-3,3,4›\r\n" );
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document.write( "So we substitute in \r\n" );
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document.write( "\"x=x%5B1%5D%2Bat\", \"y=y%5B1%5D%2Bbt\", \"z=z%5B1%5D%2Bct\"\r\n" );
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document.write( "with ‹a,b,c› = ‹-3,3,4›  and the point P(\"x%5B1%5D\",\"y%5B1%5D\",\"z%5B1%5D\") = P(2,1,-3)\r\n" );
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document.write( "\"x=2-3t\", \"y=1%2B3t\", \"z=-3%2B4t\"\r\n" );
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document.write( "That's the parametric equations for the line.\r\n" );
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document.write( "If you want the symmetric equation of the line, we\r\n" );
document.write( "substitute in\r\n" );
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document.write( "\"%28x-x%5B1%5D%29%2Fa=%28y-y%5B1%5D%29%2Fb=%28z-z%5B1%5D%29%2Fc\"\r\n" );
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document.write( "\"%28x-2%29%2F%28-3%29=%28y-1%29%2F3=%28z-%28-3%29%29%2F4\"\r\n" );
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document.write( "\"%28x-2%29%2F%28-3%29=%28y-1%29%2F3=%28z%2B3%29%2F4\"\r\n" );
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document.write( "Edwin
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