Finding a vector position












0












$begingroup$



"The position vectors of points $A$ and $B$ relative to the origin are
$3i+2j-k$ and $5i+6j+5k$ respectively. Find the position vector of the
point $P$ which lies on $AB$ produced such that $AP=3BP$."




Actually I can solve this, provided I find where P lies - on $AB$ line sector or the continuation of $AB$. That's exactly what I don't understand - how to visualize the problem.



How do I figure out where exactly $P$ lies?










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    0












    $begingroup$



    "The position vectors of points $A$ and $B$ relative to the origin are
    $3i+2j-k$ and $5i+6j+5k$ respectively. Find the position vector of the
    point $P$ which lies on $AB$ produced such that $AP=3BP$."




    Actually I can solve this, provided I find where P lies - on $AB$ line sector or the continuation of $AB$. That's exactly what I don't understand - how to visualize the problem.



    How do I figure out where exactly $P$ lies?










    share|cite|improve this question











    $endgroup$















      0












      0








      0





      $begingroup$



      "The position vectors of points $A$ and $B$ relative to the origin are
      $3i+2j-k$ and $5i+6j+5k$ respectively. Find the position vector of the
      point $P$ which lies on $AB$ produced such that $AP=3BP$."




      Actually I can solve this, provided I find where P lies - on $AB$ line sector or the continuation of $AB$. That's exactly what I don't understand - how to visualize the problem.



      How do I figure out where exactly $P$ lies?










      share|cite|improve this question











      $endgroup$





      "The position vectors of points $A$ and $B$ relative to the origin are
      $3i+2j-k$ and $5i+6j+5k$ respectively. Find the position vector of the
      point $P$ which lies on $AB$ produced such that $AP=3BP$."




      Actually I can solve this, provided I find where P lies - on $AB$ line sector or the continuation of $AB$. That's exactly what I don't understand - how to visualize the problem.



      How do I figure out where exactly $P$ lies?







      geometry vectors






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      share|cite|improve this question




      share|cite|improve this question








      edited Dec 10 '18 at 6:56









      Ali

      1,9732520




      1,9732520










      asked Dec 8 '18 at 9:02









      Windy Windy

      31




      31






















          2 Answers
          2






          active

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          0












          $begingroup$

          Since it is written that "point P which lies on AB produced", therefore P doesn't lie on line AB and given is the case of external division.



          Apply the external section formula directly.



          Hope it is helpful.






          share|cite|improve this answer









          $endgroup$













          • $begingroup$
            Thank you very much. That was it, I didn't understand the expression properly.
            $endgroup$
            – Windy
            Dec 8 '18 at 9:24



















          0












          $begingroup$

          Here's my understanding of the problem:



          enter image description here



          The point $P$ is at $A + 3/4 (B-A)$.






          share|cite|improve this answer









          $endgroup$













          • $begingroup$
            P lies on AB produced and not on AB as you are assuming.
            $endgroup$
            – Martund
            Dec 8 '18 at 9:35










          • $begingroup$
            What does "AB produced" mean?
            $endgroup$
            – David G. Stork
            Dec 8 '18 at 11:40










          • $begingroup$
            Means that you have to extend AB to get P on that, it is not on line segment AB.
            $endgroup$
            – Martund
            Dec 8 '18 at 11:46










          • $begingroup$
            "AB produced" is not standard English.
            $endgroup$
            – David G. Stork
            Dec 8 '18 at 11:48











          Your Answer





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          2 Answers
          2






          active

          oldest

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          2 Answers
          2






          active

          oldest

          votes









          active

          oldest

          votes






          active

          oldest

          votes









          0












          $begingroup$

          Since it is written that "point P which lies on AB produced", therefore P doesn't lie on line AB and given is the case of external division.



          Apply the external section formula directly.



          Hope it is helpful.






          share|cite|improve this answer









          $endgroup$













          • $begingroup$
            Thank you very much. That was it, I didn't understand the expression properly.
            $endgroup$
            – Windy
            Dec 8 '18 at 9:24
















          0












          $begingroup$

          Since it is written that "point P which lies on AB produced", therefore P doesn't lie on line AB and given is the case of external division.



          Apply the external section formula directly.



          Hope it is helpful.






          share|cite|improve this answer









          $endgroup$













          • $begingroup$
            Thank you very much. That was it, I didn't understand the expression properly.
            $endgroup$
            – Windy
            Dec 8 '18 at 9:24














          0












          0








          0





          $begingroup$

          Since it is written that "point P which lies on AB produced", therefore P doesn't lie on line AB and given is the case of external division.



          Apply the external section formula directly.



          Hope it is helpful.






          share|cite|improve this answer









          $endgroup$



          Since it is written that "point P which lies on AB produced", therefore P doesn't lie on line AB and given is the case of external division.



          Apply the external section formula directly.



          Hope it is helpful.







          share|cite|improve this answer












          share|cite|improve this answer



          share|cite|improve this answer










          answered Dec 8 '18 at 9:21









          MartundMartund

          1,633213




          1,633213












          • $begingroup$
            Thank you very much. That was it, I didn't understand the expression properly.
            $endgroup$
            – Windy
            Dec 8 '18 at 9:24


















          • $begingroup$
            Thank you very much. That was it, I didn't understand the expression properly.
            $endgroup$
            – Windy
            Dec 8 '18 at 9:24
















          $begingroup$
          Thank you very much. That was it, I didn't understand the expression properly.
          $endgroup$
          – Windy
          Dec 8 '18 at 9:24




          $begingroup$
          Thank you very much. That was it, I didn't understand the expression properly.
          $endgroup$
          – Windy
          Dec 8 '18 at 9:24











          0












          $begingroup$

          Here's my understanding of the problem:



          enter image description here



          The point $P$ is at $A + 3/4 (B-A)$.






          share|cite|improve this answer









          $endgroup$













          • $begingroup$
            P lies on AB produced and not on AB as you are assuming.
            $endgroup$
            – Martund
            Dec 8 '18 at 9:35










          • $begingroup$
            What does "AB produced" mean?
            $endgroup$
            – David G. Stork
            Dec 8 '18 at 11:40










          • $begingroup$
            Means that you have to extend AB to get P on that, it is not on line segment AB.
            $endgroup$
            – Martund
            Dec 8 '18 at 11:46










          • $begingroup$
            "AB produced" is not standard English.
            $endgroup$
            – David G. Stork
            Dec 8 '18 at 11:48
















          0












          $begingroup$

          Here's my understanding of the problem:



          enter image description here



          The point $P$ is at $A + 3/4 (B-A)$.






          share|cite|improve this answer









          $endgroup$













          • $begingroup$
            P lies on AB produced and not on AB as you are assuming.
            $endgroup$
            – Martund
            Dec 8 '18 at 9:35










          • $begingroup$
            What does "AB produced" mean?
            $endgroup$
            – David G. Stork
            Dec 8 '18 at 11:40










          • $begingroup$
            Means that you have to extend AB to get P on that, it is not on line segment AB.
            $endgroup$
            – Martund
            Dec 8 '18 at 11:46










          • $begingroup$
            "AB produced" is not standard English.
            $endgroup$
            – David G. Stork
            Dec 8 '18 at 11:48














          0












          0








          0





          $begingroup$

          Here's my understanding of the problem:



          enter image description here



          The point $P$ is at $A + 3/4 (B-A)$.






          share|cite|improve this answer









          $endgroup$



          Here's my understanding of the problem:



          enter image description here



          The point $P$ is at $A + 3/4 (B-A)$.







          share|cite|improve this answer












          share|cite|improve this answer



          share|cite|improve this answer










          answered Dec 8 '18 at 9:29









          David G. StorkDavid G. Stork

          11k41432




          11k41432












          • $begingroup$
            P lies on AB produced and not on AB as you are assuming.
            $endgroup$
            – Martund
            Dec 8 '18 at 9:35










          • $begingroup$
            What does "AB produced" mean?
            $endgroup$
            – David G. Stork
            Dec 8 '18 at 11:40










          • $begingroup$
            Means that you have to extend AB to get P on that, it is not on line segment AB.
            $endgroup$
            – Martund
            Dec 8 '18 at 11:46










          • $begingroup$
            "AB produced" is not standard English.
            $endgroup$
            – David G. Stork
            Dec 8 '18 at 11:48


















          • $begingroup$
            P lies on AB produced and not on AB as you are assuming.
            $endgroup$
            – Martund
            Dec 8 '18 at 9:35










          • $begingroup$
            What does "AB produced" mean?
            $endgroup$
            – David G. Stork
            Dec 8 '18 at 11:40










          • $begingroup$
            Means that you have to extend AB to get P on that, it is not on line segment AB.
            $endgroup$
            – Martund
            Dec 8 '18 at 11:46










          • $begingroup$
            "AB produced" is not standard English.
            $endgroup$
            – David G. Stork
            Dec 8 '18 at 11:48
















          $begingroup$
          P lies on AB produced and not on AB as you are assuming.
          $endgroup$
          – Martund
          Dec 8 '18 at 9:35




          $begingroup$
          P lies on AB produced and not on AB as you are assuming.
          $endgroup$
          – Martund
          Dec 8 '18 at 9:35












          $begingroup$
          What does "AB produced" mean?
          $endgroup$
          – David G. Stork
          Dec 8 '18 at 11:40




          $begingroup$
          What does "AB produced" mean?
          $endgroup$
          – David G. Stork
          Dec 8 '18 at 11:40












          $begingroup$
          Means that you have to extend AB to get P on that, it is not on line segment AB.
          $endgroup$
          – Martund
          Dec 8 '18 at 11:46




          $begingroup$
          Means that you have to extend AB to get P on that, it is not on line segment AB.
          $endgroup$
          – Martund
          Dec 8 '18 at 11:46












          $begingroup$
          "AB produced" is not standard English.
          $endgroup$
          – David G. Stork
          Dec 8 '18 at 11:48




          $begingroup$
          "AB produced" is not standard English.
          $endgroup$
          – David G. Stork
          Dec 8 '18 at 11:48


















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