The quadratic equation $ax^2+bx+c=0$ and $Ax^2+Bx+C$ have roots $(x_1,x_2)$ and $(x_3,x_4)$. Find the condition in which the devide.

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The quadratic equations $ax^2+bx+c=0 $ and $Ax^2+Bx+C=0$ have roots $x_1,x_2$ and $x_3,x_4$. Find the condition that the points $(x_1,0)$ and $(x_2,0)$ divide the segment between $(x_3,0)$ and $(x_4,0)$ harmonically. Given two points, $p$ and $q$ are said to divide $a b$ harmonically if one divides $a b$ internally and the other one divides $a b$ externally in the same ratio, in other words, the sum of the ratios is zero. I tried out this question using Section formula and putting the values but I could not get the desired result please help me out.







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  • Holy cow...either I'm stupid or I couldn't understand 90% of the words here.
    – Rushabh Mehta
    Aug 25 at 0:44










  • Under the interpretation that $;dfracx_1-x_3x_1-x_4+dfracx_2-x_3x_2-x_4=0,$, where did you get stuck?
    – dxiv
    Aug 25 at 0:53














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The quadratic equations $ax^2+bx+c=0 $ and $Ax^2+Bx+C=0$ have roots $x_1,x_2$ and $x_3,x_4$. Find the condition that the points $(x_1,0)$ and $(x_2,0)$ divide the segment between $(x_3,0)$ and $(x_4,0)$ harmonically. Given two points, $p$ and $q$ are said to divide $a b$ harmonically if one divides $a b$ internally and the other one divides $a b$ externally in the same ratio, in other words, the sum of the ratios is zero. I tried out this question using Section formula and putting the values but I could not get the desired result please help me out.







share|cite|improve this question






















  • Holy cow...either I'm stupid or I couldn't understand 90% of the words here.
    – Rushabh Mehta
    Aug 25 at 0:44










  • Under the interpretation that $;dfracx_1-x_3x_1-x_4+dfracx_2-x_3x_2-x_4=0,$, where did you get stuck?
    – dxiv
    Aug 25 at 0:53












up vote
0
down vote

favorite









up vote
0
down vote

favorite











The quadratic equations $ax^2+bx+c=0 $ and $Ax^2+Bx+C=0$ have roots $x_1,x_2$ and $x_3,x_4$. Find the condition that the points $(x_1,0)$ and $(x_2,0)$ divide the segment between $(x_3,0)$ and $(x_4,0)$ harmonically. Given two points, $p$ and $q$ are said to divide $a b$ harmonically if one divides $a b$ internally and the other one divides $a b$ externally in the same ratio, in other words, the sum of the ratios is zero. I tried out this question using Section formula and putting the values but I could not get the desired result please help me out.







share|cite|improve this question














The quadratic equations $ax^2+bx+c=0 $ and $Ax^2+Bx+C=0$ have roots $x_1,x_2$ and $x_3,x_4$. Find the condition that the points $(x_1,0)$ and $(x_2,0)$ divide the segment between $(x_3,0)$ and $(x_4,0)$ harmonically. Given two points, $p$ and $q$ are said to divide $a b$ harmonically if one divides $a b$ internally and the other one divides $a b$ externally in the same ratio, in other words, the sum of the ratios is zero. I tried out this question using Section formula and putting the values but I could not get the desired result please help me out.









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edited Aug 25 at 1:06









Cornman

2,70421228




2,70421228










asked Aug 25 at 0:42









user584880

91




91











  • Holy cow...either I'm stupid or I couldn't understand 90% of the words here.
    – Rushabh Mehta
    Aug 25 at 0:44










  • Under the interpretation that $;dfracx_1-x_3x_1-x_4+dfracx_2-x_3x_2-x_4=0,$, where did you get stuck?
    – dxiv
    Aug 25 at 0:53
















  • Holy cow...either I'm stupid or I couldn't understand 90% of the words here.
    – Rushabh Mehta
    Aug 25 at 0:44










  • Under the interpretation that $;dfracx_1-x_3x_1-x_4+dfracx_2-x_3x_2-x_4=0,$, where did you get stuck?
    – dxiv
    Aug 25 at 0:53















Holy cow...either I'm stupid or I couldn't understand 90% of the words here.
– Rushabh Mehta
Aug 25 at 0:44




Holy cow...either I'm stupid or I couldn't understand 90% of the words here.
– Rushabh Mehta
Aug 25 at 0:44












Under the interpretation that $;dfracx_1-x_3x_1-x_4+dfracx_2-x_3x_2-x_4=0,$, where did you get stuck?
– dxiv
Aug 25 at 0:53




Under the interpretation that $;dfracx_1-x_3x_1-x_4+dfracx_2-x_3x_2-x_4=0,$, where did you get stuck?
– dxiv
Aug 25 at 0:53










1 Answer
1






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0
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We can manipulate the relation given by dxiv as follows:



$fracx_1-x_3x_1-x_4=fracx_3-x_2x_2-x_4$



$x_1x_2 - x_1x_4-x_2x_3 +x_3x_4=x_1x_3-x_1x_2-x_3x_4+x_2x_4$



Rearranging and summing gives:



$2x_1x_2 +2x_3x_4 -x_2(x_3+x_4)-x_1(x_3+x_4)=0$



$x_1x_2=fracca$



$x_3x_4=fracCA$



$x_3+x_4=-fracBA$



$x_1+x_2=-fracba$



Substituting we get:



$2(fracca+fracCA)-fracba.fracBA=0$



Or:



$Atimes c+atimes C =fracb times B2$






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  • What is dxiv in the answer you have written?
    – user584880
    Aug 26 at 0:43










  • see second comment. he or she is the user who proposed the relation.
    – sirous
    Aug 26 at 6:24










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1 Answer
1






active

oldest

votes








1 Answer
1






active

oldest

votes









active

oldest

votes






active

oldest

votes








up vote
0
down vote













We can manipulate the relation given by dxiv as follows:



$fracx_1-x_3x_1-x_4=fracx_3-x_2x_2-x_4$



$x_1x_2 - x_1x_4-x_2x_3 +x_3x_4=x_1x_3-x_1x_2-x_3x_4+x_2x_4$



Rearranging and summing gives:



$2x_1x_2 +2x_3x_4 -x_2(x_3+x_4)-x_1(x_3+x_4)=0$



$x_1x_2=fracca$



$x_3x_4=fracCA$



$x_3+x_4=-fracBA$



$x_1+x_2=-fracba$



Substituting we get:



$2(fracca+fracCA)-fracba.fracBA=0$



Or:



$Atimes c+atimes C =fracb times B2$






share|cite|improve this answer




















  • What is dxiv in the answer you have written?
    – user584880
    Aug 26 at 0:43










  • see second comment. he or she is the user who proposed the relation.
    – sirous
    Aug 26 at 6:24














up vote
0
down vote













We can manipulate the relation given by dxiv as follows:



$fracx_1-x_3x_1-x_4=fracx_3-x_2x_2-x_4$



$x_1x_2 - x_1x_4-x_2x_3 +x_3x_4=x_1x_3-x_1x_2-x_3x_4+x_2x_4$



Rearranging and summing gives:



$2x_1x_2 +2x_3x_4 -x_2(x_3+x_4)-x_1(x_3+x_4)=0$



$x_1x_2=fracca$



$x_3x_4=fracCA$



$x_3+x_4=-fracBA$



$x_1+x_2=-fracba$



Substituting we get:



$2(fracca+fracCA)-fracba.fracBA=0$



Or:



$Atimes c+atimes C =fracb times B2$






share|cite|improve this answer




















  • What is dxiv in the answer you have written?
    – user584880
    Aug 26 at 0:43










  • see second comment. he or she is the user who proposed the relation.
    – sirous
    Aug 26 at 6:24












up vote
0
down vote










up vote
0
down vote









We can manipulate the relation given by dxiv as follows:



$fracx_1-x_3x_1-x_4=fracx_3-x_2x_2-x_4$



$x_1x_2 - x_1x_4-x_2x_3 +x_3x_4=x_1x_3-x_1x_2-x_3x_4+x_2x_4$



Rearranging and summing gives:



$2x_1x_2 +2x_3x_4 -x_2(x_3+x_4)-x_1(x_3+x_4)=0$



$x_1x_2=fracca$



$x_3x_4=fracCA$



$x_3+x_4=-fracBA$



$x_1+x_2=-fracba$



Substituting we get:



$2(fracca+fracCA)-fracba.fracBA=0$



Or:



$Atimes c+atimes C =fracb times B2$






share|cite|improve this answer












We can manipulate the relation given by dxiv as follows:



$fracx_1-x_3x_1-x_4=fracx_3-x_2x_2-x_4$



$x_1x_2 - x_1x_4-x_2x_3 +x_3x_4=x_1x_3-x_1x_2-x_3x_4+x_2x_4$



Rearranging and summing gives:



$2x_1x_2 +2x_3x_4 -x_2(x_3+x_4)-x_1(x_3+x_4)=0$



$x_1x_2=fracca$



$x_3x_4=fracCA$



$x_3+x_4=-fracBA$



$x_1+x_2=-fracba$



Substituting we get:



$2(fracca+fracCA)-fracba.fracBA=0$



Or:



$Atimes c+atimes C =fracb times B2$







share|cite|improve this answer












share|cite|improve this answer



share|cite|improve this answer










answered Aug 25 at 17:55









sirous

931512




931512











  • What is dxiv in the answer you have written?
    – user584880
    Aug 26 at 0:43










  • see second comment. he or she is the user who proposed the relation.
    – sirous
    Aug 26 at 6:24
















  • What is dxiv in the answer you have written?
    – user584880
    Aug 26 at 0:43










  • see second comment. he or she is the user who proposed the relation.
    – sirous
    Aug 26 at 6:24















What is dxiv in the answer you have written?
– user584880
Aug 26 at 0:43




What is dxiv in the answer you have written?
– user584880
Aug 26 at 0:43












see second comment. he or she is the user who proposed the relation.
– sirous
Aug 26 at 6:24




see second comment. he or she is the user who proposed the relation.
– sirous
Aug 26 at 6:24

















 

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