document.write( "Question 837215: sir please help me i badly need it now.. thanks..
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document.write( "Find the equation of the line through (-3,5) which makes the angle of 45 degrees with the line 2x+y=12 . its analytic geometry sir.. \n" );
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Algebra.Com's Answer #504543 by LinnW(1048)![]() ![]() You can put this solution on YOUR website! \r \n" ); document.write( "\n" ); document.write( "Let's find the equation of a line through (-3,5) \n" ); document.write( "that is perpendicular to y = -2x + 12\r \n" ); document.write( "\n" ); document.write( "First find the slope of 2x + y = 12 \n" ); document.write( "add -2x to each side \n" ); document.write( "y = -2x + 12 \n" ); document.write( "slope is -2 \n" ); document.write( "so slope of perpendicular is 1/2 \n" ); document.write( "To find the slope of a line that is 45 degrees \n" ); document.write( "offset, consider equations with slopes -2 and 1/2 \n" ); document.write( "the pass through (0,0) \n" ); document.write( "y =-2x and y = (1/2)x \n" ); document.write( "Let L = the length of the segment between \n" ); document.write( "(0,0) and (1,-2) , points on the line y = -2x \n" ); document.write( "The length of the segment between \n" ); document.write( "(0,0) and (2,1) is equal L and on the line y = (1/2)x \n" ); document.write( "The segment between (0,0) and the midpoint \n" ); document.write( "between (1,-2) and (2,1) will bisect the two lines \n" ); document.write( "and the angle will be 45 degrees from each. \n" ); document.write( "The midpoint is ( (1+2)/2 , (-2+1)/2 ) \n" ); document.write( "= ( 3/2 , -1/2) \n" ); document.write( "The slope of the line through (0,0) and ( 3/2 , -1/2 ) \n" ); document.write( "is (-1/2)/(3/2) = -1/3 \n" ); document.write( "A line though (-3,5) with a slope of -1/3 will \n" ); document.write( "be 45 degrees offset from 2x+y=12 \n" ); document.write( "y = mx + b \n" ); document.write( "5 = (-1/3)(-3) + b \n" ); document.write( "5 = 1 + b \n" ); document.write( "4 = b \n" ); document.write( "Our equation is y = (-1/3)x + 4 \n" ); document.write( "Check out the following link to see the plot. \n" ); document.write( "http://www.wolframalpha.com/input/?i=plot+y%3D-x%2F3+%2B4++and+2x%2By%3D12 \n" ); document.write( " \n" ); document.write( " |