Point on the square with a circle inscribed inside it












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I giving a second try to this question. Hopefully, with better problem definition.



I have a circle inscribed inside a square and would like to know the point the radius touches when extended. In the figure A, we have calculated the angle(θ), C(center) , D and E. How do i calculate the (x,y) of A and B?



enter image description here










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    0












    $begingroup$


    I giving a second try to this question. Hopefully, with better problem definition.



    I have a circle inscribed inside a square and would like to know the point the radius touches when extended. In the figure A, we have calculated the angle(θ), C(center) , D and E. How do i calculate the (x,y) of A and B?



    enter image description here










    share|cite|improve this question











    $endgroup$















      0












      0








      0





      $begingroup$


      I giving a second try to this question. Hopefully, with better problem definition.



      I have a circle inscribed inside a square and would like to know the point the radius touches when extended. In the figure A, we have calculated the angle(θ), C(center) , D and E. How do i calculate the (x,y) of A and B?



      enter image description here










      share|cite|improve this question











      $endgroup$




      I giving a second try to this question. Hopefully, with better problem definition.



      I have a circle inscribed inside a square and would like to know the point the radius touches when extended. In the figure A, we have calculated the angle(θ), C(center) , D and E. How do i calculate the (x,y) of A and B?



      enter image description here







      geometry trigonometry coordinate-systems






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      edited Dec 31 '18 at 15:45









      saulspatz

      17k31435




      17k31435










      asked Dec 31 '18 at 15:40









      brainfreakbrainfreak

      13




      13






















          3 Answers
          3






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          1












          $begingroup$

          In the case you've drawn, you already know the $x$ value, assuming the circle has center in $(C_x,C_y)$ and radius $r$, $A_x=B_x=C_x+r.$ As for the $y,$ a little trigonometry helps: $A_y=C_y+r·tan theta.$






          share|cite|improve this answer









          $endgroup$





















            0












            $begingroup$

            If you know the coordinates of the center then you add $r$ to the $x$ coordinate and you add $r tan (theta)$ to the $y$ coordinate of the center to get coordinates of $A$



            Similarly you can find coordinates of $B$






            share|cite|improve this answer









            $endgroup$





















              0












              $begingroup$

              Describe the circle as
              $$vec x=vec m+begin{pmatrix} rcos(t)\ rsin(t)
              end{pmatrix}.$$

              Now consider the ray
              $$vec y=vec m+lambdabegin{pmatrix} rcos(t)\ rsin(t)
              end{pmatrix}$$

              with $lambda>0$.
              You want to have the first coordinate for $tin(-pi/2,pi/2)$ of $vec y$ to be $m_1+r$, hence $lambda=1/cos(t)$ and the desired point is
              $$vec m+frac{1}{cos(t)}begin{pmatrix} rcos(t)\ rsin(t)
              end{pmatrix}=begin{pmatrix} m_1+r\ m_2+rtan(t)
              end{pmatrix}.$$






              share|cite|improve this answer









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                3 Answers
                3






                active

                oldest

                votes








                3 Answers
                3






                active

                oldest

                votes









                active

                oldest

                votes






                active

                oldest

                votes









                1












                $begingroup$

                In the case you've drawn, you already know the $x$ value, assuming the circle has center in $(C_x,C_y)$ and radius $r$, $A_x=B_x=C_x+r.$ As for the $y,$ a little trigonometry helps: $A_y=C_y+r·tan theta.$






                share|cite|improve this answer









                $endgroup$


















                  1












                  $begingroup$

                  In the case you've drawn, you already know the $x$ value, assuming the circle has center in $(C_x,C_y)$ and radius $r$, $A_x=B_x=C_x+r.$ As for the $y,$ a little trigonometry helps: $A_y=C_y+r·tan theta.$






                  share|cite|improve this answer









                  $endgroup$
















                    1












                    1








                    1





                    $begingroup$

                    In the case you've drawn, you already know the $x$ value, assuming the circle has center in $(C_x,C_y)$ and radius $r$, $A_x=B_x=C_x+r.$ As for the $y,$ a little trigonometry helps: $A_y=C_y+r·tan theta.$






                    share|cite|improve this answer









                    $endgroup$



                    In the case you've drawn, you already know the $x$ value, assuming the circle has center in $(C_x,C_y)$ and radius $r$, $A_x=B_x=C_x+r.$ As for the $y,$ a little trigonometry helps: $A_y=C_y+r·tan theta.$







                    share|cite|improve this answer












                    share|cite|improve this answer



                    share|cite|improve this answer










                    answered Dec 31 '18 at 15:56









                    PatricioPatricio

                    3427




                    3427























                        0












                        $begingroup$

                        If you know the coordinates of the center then you add $r$ to the $x$ coordinate and you add $r tan (theta)$ to the $y$ coordinate of the center to get coordinates of $A$



                        Similarly you can find coordinates of $B$






                        share|cite|improve this answer









                        $endgroup$


















                          0












                          $begingroup$

                          If you know the coordinates of the center then you add $r$ to the $x$ coordinate and you add $r tan (theta)$ to the $y$ coordinate of the center to get coordinates of $A$



                          Similarly you can find coordinates of $B$






                          share|cite|improve this answer









                          $endgroup$
















                            0












                            0








                            0





                            $begingroup$

                            If you know the coordinates of the center then you add $r$ to the $x$ coordinate and you add $r tan (theta)$ to the $y$ coordinate of the center to get coordinates of $A$



                            Similarly you can find coordinates of $B$






                            share|cite|improve this answer









                            $endgroup$



                            If you know the coordinates of the center then you add $r$ to the $x$ coordinate and you add $r tan (theta)$ to the $y$ coordinate of the center to get coordinates of $A$



                            Similarly you can find coordinates of $B$







                            share|cite|improve this answer












                            share|cite|improve this answer



                            share|cite|improve this answer










                            answered Dec 31 '18 at 15:55









                            Mohammad Riazi-KermaniMohammad Riazi-Kermani

                            41.6k42061




                            41.6k42061























                                0












                                $begingroup$

                                Describe the circle as
                                $$vec x=vec m+begin{pmatrix} rcos(t)\ rsin(t)
                                end{pmatrix}.$$

                                Now consider the ray
                                $$vec y=vec m+lambdabegin{pmatrix} rcos(t)\ rsin(t)
                                end{pmatrix}$$

                                with $lambda>0$.
                                You want to have the first coordinate for $tin(-pi/2,pi/2)$ of $vec y$ to be $m_1+r$, hence $lambda=1/cos(t)$ and the desired point is
                                $$vec m+frac{1}{cos(t)}begin{pmatrix} rcos(t)\ rsin(t)
                                end{pmatrix}=begin{pmatrix} m_1+r\ m_2+rtan(t)
                                end{pmatrix}.$$






                                share|cite|improve this answer









                                $endgroup$


















                                  0












                                  $begingroup$

                                  Describe the circle as
                                  $$vec x=vec m+begin{pmatrix} rcos(t)\ rsin(t)
                                  end{pmatrix}.$$

                                  Now consider the ray
                                  $$vec y=vec m+lambdabegin{pmatrix} rcos(t)\ rsin(t)
                                  end{pmatrix}$$

                                  with $lambda>0$.
                                  You want to have the first coordinate for $tin(-pi/2,pi/2)$ of $vec y$ to be $m_1+r$, hence $lambda=1/cos(t)$ and the desired point is
                                  $$vec m+frac{1}{cos(t)}begin{pmatrix} rcos(t)\ rsin(t)
                                  end{pmatrix}=begin{pmatrix} m_1+r\ m_2+rtan(t)
                                  end{pmatrix}.$$






                                  share|cite|improve this answer









                                  $endgroup$
















                                    0












                                    0








                                    0





                                    $begingroup$

                                    Describe the circle as
                                    $$vec x=vec m+begin{pmatrix} rcos(t)\ rsin(t)
                                    end{pmatrix}.$$

                                    Now consider the ray
                                    $$vec y=vec m+lambdabegin{pmatrix} rcos(t)\ rsin(t)
                                    end{pmatrix}$$

                                    with $lambda>0$.
                                    You want to have the first coordinate for $tin(-pi/2,pi/2)$ of $vec y$ to be $m_1+r$, hence $lambda=1/cos(t)$ and the desired point is
                                    $$vec m+frac{1}{cos(t)}begin{pmatrix} rcos(t)\ rsin(t)
                                    end{pmatrix}=begin{pmatrix} m_1+r\ m_2+rtan(t)
                                    end{pmatrix}.$$






                                    share|cite|improve this answer









                                    $endgroup$



                                    Describe the circle as
                                    $$vec x=vec m+begin{pmatrix} rcos(t)\ rsin(t)
                                    end{pmatrix}.$$

                                    Now consider the ray
                                    $$vec y=vec m+lambdabegin{pmatrix} rcos(t)\ rsin(t)
                                    end{pmatrix}$$

                                    with $lambda>0$.
                                    You want to have the first coordinate for $tin(-pi/2,pi/2)$ of $vec y$ to be $m_1+r$, hence $lambda=1/cos(t)$ and the desired point is
                                    $$vec m+frac{1}{cos(t)}begin{pmatrix} rcos(t)\ rsin(t)
                                    end{pmatrix}=begin{pmatrix} m_1+r\ m_2+rtan(t)
                                    end{pmatrix}.$$







                                    share|cite|improve this answer












                                    share|cite|improve this answer



                                    share|cite|improve this answer










                                    answered Dec 31 '18 at 16:14









                                    Michael HoppeMichael Hoppe

                                    11.2k31837




                                    11.2k31837






























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