Finding Tangent Plane

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I was given the following theorems:



  1. let $M$ be a $k$ dimension manifold defined by $M=ain mathbbR^n:F(x)=0$ when $Fin C^1$ and Rank$(D_f(x))$ is maximal for all $ain M$ so $T_a(M)=vin mathbbR^n:D_F(x)v=0$


  2. Let $M$ be a $k$ dimension manifold with atlas $A$ so for all $ain M$
    $T_a(M)=t_1fracpartial phipartial x_1(x)+...t_kfracpartial phipartial x_k(x)$ where $t_1,t_2,...,t_kin mathbbR$, $phiin A$ such that $phi(x)=a$


Now I am trying to find the tangent plane of using those theorems:



a. $S=(x,y): x^2+y^2=R^2$ at $(fracRsqrt2,-fracRsqrt2)$



b. $z=x^2+y^2+5$ at $(1,1,7)$



a by 1: First we set $F=x^2+y^2$ now we take $D_F=beginpmatrix
fracpartial Fpartial x & fracpartial Fpartial y
endpmatrix=beginpmatrix
2x & 2y \
endpmatrix$



(we have to check that that the Rank of $D_F$ is maximal for all $ain M$? what if it is not?)



For any $(a_1,a_2)=ain x^2+y^2$ the Rank of $(2a_1 , 2a_2)$ will be at most $1$ as else we had $S=(0,0)$



now we take the dot product $beginpmatrix
2x & 2y
endpmatrix beginpmatrix
fracRsqrt2 \
-fracRsqrt2
endpmatrix=0iff=Rsqrt2x-Rsqrt2y=0iff Rsqrt2(x-y)=0$ so $x=y$?



b by 1: $F=z-x^2-y^2$ now $D_F=beginpmatrix
fracpartial Fpartial x & fracpartial Fpartial y & fracpartial Fpartial z
endpmatrix=beginpmatrix
-2x & -2y & 1 \
endpmatrix$ So $beginpmatrix
-2x & -2y & 1 \
endpmatrixbeginpmatrix
1 \
1 \
7
endpmatrix=0iff -2x-2y+7=0iff 2x+2y=7$



Is it correct? How can I use method $2$ to find the tangent plane?







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    I was given the following theorems:



    1. let $M$ be a $k$ dimension manifold defined by $M=ain mathbbR^n:F(x)=0$ when $Fin C^1$ and Rank$(D_f(x))$ is maximal for all $ain M$ so $T_a(M)=vin mathbbR^n:D_F(x)v=0$


    2. Let $M$ be a $k$ dimension manifold with atlas $A$ so for all $ain M$
      $T_a(M)=t_1fracpartial phipartial x_1(x)+...t_kfracpartial phipartial x_k(x)$ where $t_1,t_2,...,t_kin mathbbR$, $phiin A$ such that $phi(x)=a$


    Now I am trying to find the tangent plane of using those theorems:



    a. $S=(x,y): x^2+y^2=R^2$ at $(fracRsqrt2,-fracRsqrt2)$



    b. $z=x^2+y^2+5$ at $(1,1,7)$



    a by 1: First we set $F=x^2+y^2$ now we take $D_F=beginpmatrix
    fracpartial Fpartial x & fracpartial Fpartial y
    endpmatrix=beginpmatrix
    2x & 2y \
    endpmatrix$



    (we have to check that that the Rank of $D_F$ is maximal for all $ain M$? what if it is not?)



    For any $(a_1,a_2)=ain x^2+y^2$ the Rank of $(2a_1 , 2a_2)$ will be at most $1$ as else we had $S=(0,0)$



    now we take the dot product $beginpmatrix
    2x & 2y
    endpmatrix beginpmatrix
    fracRsqrt2 \
    -fracRsqrt2
    endpmatrix=0iff=Rsqrt2x-Rsqrt2y=0iff Rsqrt2(x-y)=0$ so $x=y$?



    b by 1: $F=z-x^2-y^2$ now $D_F=beginpmatrix
    fracpartial Fpartial x & fracpartial Fpartial y & fracpartial Fpartial z
    endpmatrix=beginpmatrix
    -2x & -2y & 1 \
    endpmatrix$ So $beginpmatrix
    -2x & -2y & 1 \
    endpmatrixbeginpmatrix
    1 \
    1 \
    7
    endpmatrix=0iff -2x-2y+7=0iff 2x+2y=7$



    Is it correct? How can I use method $2$ to find the tangent plane?







    share|cite|improve this question























      up vote
      0
      down vote

      favorite









      up vote
      0
      down vote

      favorite











      I was given the following theorems:



      1. let $M$ be a $k$ dimension manifold defined by $M=ain mathbbR^n:F(x)=0$ when $Fin C^1$ and Rank$(D_f(x))$ is maximal for all $ain M$ so $T_a(M)=vin mathbbR^n:D_F(x)v=0$


      2. Let $M$ be a $k$ dimension manifold with atlas $A$ so for all $ain M$
        $T_a(M)=t_1fracpartial phipartial x_1(x)+...t_kfracpartial phipartial x_k(x)$ where $t_1,t_2,...,t_kin mathbbR$, $phiin A$ such that $phi(x)=a$


      Now I am trying to find the tangent plane of using those theorems:



      a. $S=(x,y): x^2+y^2=R^2$ at $(fracRsqrt2,-fracRsqrt2)$



      b. $z=x^2+y^2+5$ at $(1,1,7)$



      a by 1: First we set $F=x^2+y^2$ now we take $D_F=beginpmatrix
      fracpartial Fpartial x & fracpartial Fpartial y
      endpmatrix=beginpmatrix
      2x & 2y \
      endpmatrix$



      (we have to check that that the Rank of $D_F$ is maximal for all $ain M$? what if it is not?)



      For any $(a_1,a_2)=ain x^2+y^2$ the Rank of $(2a_1 , 2a_2)$ will be at most $1$ as else we had $S=(0,0)$



      now we take the dot product $beginpmatrix
      2x & 2y
      endpmatrix beginpmatrix
      fracRsqrt2 \
      -fracRsqrt2
      endpmatrix=0iff=Rsqrt2x-Rsqrt2y=0iff Rsqrt2(x-y)=0$ so $x=y$?



      b by 1: $F=z-x^2-y^2$ now $D_F=beginpmatrix
      fracpartial Fpartial x & fracpartial Fpartial y & fracpartial Fpartial z
      endpmatrix=beginpmatrix
      -2x & -2y & 1 \
      endpmatrix$ So $beginpmatrix
      -2x & -2y & 1 \
      endpmatrixbeginpmatrix
      1 \
      1 \
      7
      endpmatrix=0iff -2x-2y+7=0iff 2x+2y=7$



      Is it correct? How can I use method $2$ to find the tangent plane?







      share|cite|improve this question













      I was given the following theorems:



      1. let $M$ be a $k$ dimension manifold defined by $M=ain mathbbR^n:F(x)=0$ when $Fin C^1$ and Rank$(D_f(x))$ is maximal for all $ain M$ so $T_a(M)=vin mathbbR^n:D_F(x)v=0$


      2. Let $M$ be a $k$ dimension manifold with atlas $A$ so for all $ain M$
        $T_a(M)=t_1fracpartial phipartial x_1(x)+...t_kfracpartial phipartial x_k(x)$ where $t_1,t_2,...,t_kin mathbbR$, $phiin A$ such that $phi(x)=a$


      Now I am trying to find the tangent plane of using those theorems:



      a. $S=(x,y): x^2+y^2=R^2$ at $(fracRsqrt2,-fracRsqrt2)$



      b. $z=x^2+y^2+5$ at $(1,1,7)$



      a by 1: First we set $F=x^2+y^2$ now we take $D_F=beginpmatrix
      fracpartial Fpartial x & fracpartial Fpartial y
      endpmatrix=beginpmatrix
      2x & 2y \
      endpmatrix$



      (we have to check that that the Rank of $D_F$ is maximal for all $ain M$? what if it is not?)



      For any $(a_1,a_2)=ain x^2+y^2$ the Rank of $(2a_1 , 2a_2)$ will be at most $1$ as else we had $S=(0,0)$



      now we take the dot product $beginpmatrix
      2x & 2y
      endpmatrix beginpmatrix
      fracRsqrt2 \
      -fracRsqrt2
      endpmatrix=0iff=Rsqrt2x-Rsqrt2y=0iff Rsqrt2(x-y)=0$ so $x=y$?



      b by 1: $F=z-x^2-y^2$ now $D_F=beginpmatrix
      fracpartial Fpartial x & fracpartial Fpartial y & fracpartial Fpartial z
      endpmatrix=beginpmatrix
      -2x & -2y & 1 \
      endpmatrix$ So $beginpmatrix
      -2x & -2y & 1 \
      endpmatrixbeginpmatrix
      1 \
      1 \
      7
      endpmatrix=0iff -2x-2y+7=0iff 2x+2y=7$



      Is it correct? How can I use method $2$ to find the tangent plane?









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      share|cite|improve this question




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      edited Jul 30 at 13:01
























      asked Jul 30 at 9:56









      newhere

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          If the smooth manifold is given by $vecF(X) = vec0$, then the tangent space to the manifold at point $A$ is the null space (or kernel) of $D_XF(A)$.



          In your case, $X = beginbmatrixx \ y \ z endbmatrix$ ,
          $A=beginbmatrix1 \ 1 \ 7 endbmatrix$,
          $F(X) = z-x^2-y^2$, and the manifold is given by $F(X)=0$.



          $D_XF(A) = [-2*1, -2*1, 1*7] = [-2,-2,7]$.



          The tangent space at $A$ is the solution $vecdotX = beginbmatrixdotx \ doty \ dotz endbmatrix$ to $[-2,-2,7]vecdotX = 0$



          To get the points on the tangent plane at A, add $veca$ to the vectors $vecdotX$ belonging to tangent space.



          Hope that helps!






          share|cite|improve this answer





















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            1 Answer
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            up vote
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            down vote













            If the smooth manifold is given by $vecF(X) = vec0$, then the tangent space to the manifold at point $A$ is the null space (or kernel) of $D_XF(A)$.



            In your case, $X = beginbmatrixx \ y \ z endbmatrix$ ,
            $A=beginbmatrix1 \ 1 \ 7 endbmatrix$,
            $F(X) = z-x^2-y^2$, and the manifold is given by $F(X)=0$.



            $D_XF(A) = [-2*1, -2*1, 1*7] = [-2,-2,7]$.



            The tangent space at $A$ is the solution $vecdotX = beginbmatrixdotx \ doty \ dotz endbmatrix$ to $[-2,-2,7]vecdotX = 0$



            To get the points on the tangent plane at A, add $veca$ to the vectors $vecdotX$ belonging to tangent space.



            Hope that helps!






            share|cite|improve this answer

























              up vote
              0
              down vote













              If the smooth manifold is given by $vecF(X) = vec0$, then the tangent space to the manifold at point $A$ is the null space (or kernel) of $D_XF(A)$.



              In your case, $X = beginbmatrixx \ y \ z endbmatrix$ ,
              $A=beginbmatrix1 \ 1 \ 7 endbmatrix$,
              $F(X) = z-x^2-y^2$, and the manifold is given by $F(X)=0$.



              $D_XF(A) = [-2*1, -2*1, 1*7] = [-2,-2,7]$.



              The tangent space at $A$ is the solution $vecdotX = beginbmatrixdotx \ doty \ dotz endbmatrix$ to $[-2,-2,7]vecdotX = 0$



              To get the points on the tangent plane at A, add $veca$ to the vectors $vecdotX$ belonging to tangent space.



              Hope that helps!






              share|cite|improve this answer























                up vote
                0
                down vote










                up vote
                0
                down vote









                If the smooth manifold is given by $vecF(X) = vec0$, then the tangent space to the manifold at point $A$ is the null space (or kernel) of $D_XF(A)$.



                In your case, $X = beginbmatrixx \ y \ z endbmatrix$ ,
                $A=beginbmatrix1 \ 1 \ 7 endbmatrix$,
                $F(X) = z-x^2-y^2$, and the manifold is given by $F(X)=0$.



                $D_XF(A) = [-2*1, -2*1, 1*7] = [-2,-2,7]$.



                The tangent space at $A$ is the solution $vecdotX = beginbmatrixdotx \ doty \ dotz endbmatrix$ to $[-2,-2,7]vecdotX = 0$



                To get the points on the tangent plane at A, add $veca$ to the vectors $vecdotX$ belonging to tangent space.



                Hope that helps!






                share|cite|improve this answer













                If the smooth manifold is given by $vecF(X) = vec0$, then the tangent space to the manifold at point $A$ is the null space (or kernel) of $D_XF(A)$.



                In your case, $X = beginbmatrixx \ y \ z endbmatrix$ ,
                $A=beginbmatrix1 \ 1 \ 7 endbmatrix$,
                $F(X) = z-x^2-y^2$, and the manifold is given by $F(X)=0$.



                $D_XF(A) = [-2*1, -2*1, 1*7] = [-2,-2,7]$.



                The tangent space at $A$ is the solution $vecdotX = beginbmatrixdotx \ doty \ dotz endbmatrix$ to $[-2,-2,7]vecdotX = 0$



                To get the points on the tangent plane at A, add $veca$ to the vectors $vecdotX$ belonging to tangent space.



                Hope that helps!







                share|cite|improve this answer













                share|cite|improve this answer



                share|cite|improve this answer











                answered Jul 30 at 11:50









                Suhan Shetty

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