Finding an orthonormal basis of the subspace using Gram-Schmidt method

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Apply the Gram-Schmidt orthonormalization process to the vectors $[1,3,2]^T$ and $[1,0,1]^T$ in order to get an orthonormal basis of the subspace that they span.




My Try:



I took $u_1=[1,3,2]^T,u_2=[1,0,1]^T$ and used the formula $V_1=dfracu_1u_1$ and $V_2=dfracu_2-langle u_2V_1rangle V_1$



I got $V_1=left[dfrac1sqrt14,dfrac3sqrt14,dfrac2sqrt14right]^T$



Now, I don't whether I am doing correct for $V_2$ or not. But this is what I did.



$$langle u_2V_1rangle V_1=left<(1,0,1)^Tleft(dfrac1sqrt14,dfrac3sqrt14,dfrac2sqrt14right)^Tright>^Tleft<dfrac1sqrt14,dfrac3sqrt14,dfrac2sqrt14right>^T=left<frac314,frac914,frac614right>^T$$
and $$u_2-langle u_2V_1rangle V_1=left<frac1114,frac-914,frac414right>^T$$
$$V_2=left<frac11sqrt218,frac-9sqrt218,frac4sqrt218right>^T$$



Is my $V_2$ correct?







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  • 1




    1) are your two solution vectors unit-length? 2) are they orthogonal? 3) do they span the correct subspace (easiest check is to see if they’re orthogonal to the cross product of the two input vectors)?
    – user7530
    Jul 22 at 22:42










  • @user7530 You mean do I need to do dot product of $V_1cdot V_2$ to check those?
    – philip
    Jul 22 at 22:43














up vote
1
down vote

favorite













Apply the Gram-Schmidt orthonormalization process to the vectors $[1,3,2]^T$ and $[1,0,1]^T$ in order to get an orthonormal basis of the subspace that they span.




My Try:



I took $u_1=[1,3,2]^T,u_2=[1,0,1]^T$ and used the formula $V_1=dfracu_1u_1$ and $V_2=dfracu_2-langle u_2V_1rangle V_1$



I got $V_1=left[dfrac1sqrt14,dfrac3sqrt14,dfrac2sqrt14right]^T$



Now, I don't whether I am doing correct for $V_2$ or not. But this is what I did.



$$langle u_2V_1rangle V_1=left<(1,0,1)^Tleft(dfrac1sqrt14,dfrac3sqrt14,dfrac2sqrt14right)^Tright>^Tleft<dfrac1sqrt14,dfrac3sqrt14,dfrac2sqrt14right>^T=left<frac314,frac914,frac614right>^T$$
and $$u_2-langle u_2V_1rangle V_1=left<frac1114,frac-914,frac414right>^T$$
$$V_2=left<frac11sqrt218,frac-9sqrt218,frac4sqrt218right>^T$$



Is my $V_2$ correct?







share|cite|improve this question

















  • 1




    1) are your two solution vectors unit-length? 2) are they orthogonal? 3) do they span the correct subspace (easiest check is to see if they’re orthogonal to the cross product of the two input vectors)?
    – user7530
    Jul 22 at 22:42










  • @user7530 You mean do I need to do dot product of $V_1cdot V_2$ to check those?
    – philip
    Jul 22 at 22:43












up vote
1
down vote

favorite









up vote
1
down vote

favorite












Apply the Gram-Schmidt orthonormalization process to the vectors $[1,3,2]^T$ and $[1,0,1]^T$ in order to get an orthonormal basis of the subspace that they span.




My Try:



I took $u_1=[1,3,2]^T,u_2=[1,0,1]^T$ and used the formula $V_1=dfracu_1u_1$ and $V_2=dfracu_2-langle u_2V_1rangle V_1$



I got $V_1=left[dfrac1sqrt14,dfrac3sqrt14,dfrac2sqrt14right]^T$



Now, I don't whether I am doing correct for $V_2$ or not. But this is what I did.



$$langle u_2V_1rangle V_1=left<(1,0,1)^Tleft(dfrac1sqrt14,dfrac3sqrt14,dfrac2sqrt14right)^Tright>^Tleft<dfrac1sqrt14,dfrac3sqrt14,dfrac2sqrt14right>^T=left<frac314,frac914,frac614right>^T$$
and $$u_2-langle u_2V_1rangle V_1=left<frac1114,frac-914,frac414right>^T$$
$$V_2=left<frac11sqrt218,frac-9sqrt218,frac4sqrt218right>^T$$



Is my $V_2$ correct?







share|cite|improve this question














Apply the Gram-Schmidt orthonormalization process to the vectors $[1,3,2]^T$ and $[1,0,1]^T$ in order to get an orthonormal basis of the subspace that they span.




My Try:



I took $u_1=[1,3,2]^T,u_2=[1,0,1]^T$ and used the formula $V_1=dfracu_1u_1$ and $V_2=dfracu_2-langle u_2V_1rangle V_1$



I got $V_1=left[dfrac1sqrt14,dfrac3sqrt14,dfrac2sqrt14right]^T$



Now, I don't whether I am doing correct for $V_2$ or not. But this is what I did.



$$langle u_2V_1rangle V_1=left<(1,0,1)^Tleft(dfrac1sqrt14,dfrac3sqrt14,dfrac2sqrt14right)^Tright>^Tleft<dfrac1sqrt14,dfrac3sqrt14,dfrac2sqrt14right>^T=left<frac314,frac914,frac614right>^T$$
and $$u_2-langle u_2V_1rangle V_1=left<frac1114,frac-914,frac414right>^T$$
$$V_2=left<frac11sqrt218,frac-9sqrt218,frac4sqrt218right>^T$$



Is my $V_2$ correct?









share|cite|improve this question












share|cite|improve this question




share|cite|improve this question








edited Jul 22 at 23:01









mechanodroid

22.2k52041




22.2k52041









asked Jul 22 at 22:36









philip

1158




1158







  • 1




    1) are your two solution vectors unit-length? 2) are they orthogonal? 3) do they span the correct subspace (easiest check is to see if they’re orthogonal to the cross product of the two input vectors)?
    – user7530
    Jul 22 at 22:42










  • @user7530 You mean do I need to do dot product of $V_1cdot V_2$ to check those?
    – philip
    Jul 22 at 22:43












  • 1




    1) are your two solution vectors unit-length? 2) are they orthogonal? 3) do they span the correct subspace (easiest check is to see if they’re orthogonal to the cross product of the two input vectors)?
    – user7530
    Jul 22 at 22:42










  • @user7530 You mean do I need to do dot product of $V_1cdot V_2$ to check those?
    – philip
    Jul 22 at 22:43







1




1




1) are your two solution vectors unit-length? 2) are they orthogonal? 3) do they span the correct subspace (easiest check is to see if they’re orthogonal to the cross product of the two input vectors)?
– user7530
Jul 22 at 22:42




1) are your two solution vectors unit-length? 2) are they orthogonal? 3) do they span the correct subspace (easiest check is to see if they’re orthogonal to the cross product of the two input vectors)?
– user7530
Jul 22 at 22:42












@user7530 You mean do I need to do dot product of $V_1cdot V_2$ to check those?
– philip
Jul 22 at 22:43




@user7530 You mean do I need to do dot product of $V_1cdot V_2$ to check those?
– philip
Jul 22 at 22:43










1 Answer
1






active

oldest

votes

















up vote
1
down vote



accepted










You made a small mistake, it should be:



$$u_2-langle u_2,V_1rangle V_1=left<frac1114,frac-914,fraccolorred814right>^T$$



and then



$$V_2 = left<frac11sqrt266,frac-9sqrt266,frac8sqrt266right>^T$$



Now you can check that $|V_1| = |V_2| = 1$ and $langle V_1, V_2rangle = 0$ so they are correct.






share|cite|improve this answer





















  • Thanks for the verification and for finding the mistake.
    – philip
    Jul 22 at 23:00










  • then how to verify if I had $V_1,V_2,V_3$
    – philip
    Jul 22 at 23:31










  • @philip $|V_1| = |V_2| = |V_3| = 1$ and $langle V_1, V_2rangle = langle V_1, V_3rangle = langle V_2, V_3rangle = 0$.
    – mechanodroid
    Jul 22 at 23:39










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1 Answer
1






active

oldest

votes








1 Answer
1






active

oldest

votes









active

oldest

votes






active

oldest

votes








up vote
1
down vote



accepted










You made a small mistake, it should be:



$$u_2-langle u_2,V_1rangle V_1=left<frac1114,frac-914,fraccolorred814right>^T$$



and then



$$V_2 = left<frac11sqrt266,frac-9sqrt266,frac8sqrt266right>^T$$



Now you can check that $|V_1| = |V_2| = 1$ and $langle V_1, V_2rangle = 0$ so they are correct.






share|cite|improve this answer





















  • Thanks for the verification and for finding the mistake.
    – philip
    Jul 22 at 23:00










  • then how to verify if I had $V_1,V_2,V_3$
    – philip
    Jul 22 at 23:31










  • @philip $|V_1| = |V_2| = |V_3| = 1$ and $langle V_1, V_2rangle = langle V_1, V_3rangle = langle V_2, V_3rangle = 0$.
    – mechanodroid
    Jul 22 at 23:39














up vote
1
down vote



accepted










You made a small mistake, it should be:



$$u_2-langle u_2,V_1rangle V_1=left<frac1114,frac-914,fraccolorred814right>^T$$



and then



$$V_2 = left<frac11sqrt266,frac-9sqrt266,frac8sqrt266right>^T$$



Now you can check that $|V_1| = |V_2| = 1$ and $langle V_1, V_2rangle = 0$ so they are correct.






share|cite|improve this answer





















  • Thanks for the verification and for finding the mistake.
    – philip
    Jul 22 at 23:00










  • then how to verify if I had $V_1,V_2,V_3$
    – philip
    Jul 22 at 23:31










  • @philip $|V_1| = |V_2| = |V_3| = 1$ and $langle V_1, V_2rangle = langle V_1, V_3rangle = langle V_2, V_3rangle = 0$.
    – mechanodroid
    Jul 22 at 23:39












up vote
1
down vote



accepted







up vote
1
down vote



accepted






You made a small mistake, it should be:



$$u_2-langle u_2,V_1rangle V_1=left<frac1114,frac-914,fraccolorred814right>^T$$



and then



$$V_2 = left<frac11sqrt266,frac-9sqrt266,frac8sqrt266right>^T$$



Now you can check that $|V_1| = |V_2| = 1$ and $langle V_1, V_2rangle = 0$ so they are correct.






share|cite|improve this answer













You made a small mistake, it should be:



$$u_2-langle u_2,V_1rangle V_1=left<frac1114,frac-914,fraccolorred814right>^T$$



and then



$$V_2 = left<frac11sqrt266,frac-9sqrt266,frac8sqrt266right>^T$$



Now you can check that $|V_1| = |V_2| = 1$ and $langle V_1, V_2rangle = 0$ so they are correct.







share|cite|improve this answer













share|cite|improve this answer



share|cite|improve this answer











answered Jul 22 at 22:59









mechanodroid

22.2k52041




22.2k52041











  • Thanks for the verification and for finding the mistake.
    – philip
    Jul 22 at 23:00










  • then how to verify if I had $V_1,V_2,V_3$
    – philip
    Jul 22 at 23:31










  • @philip $|V_1| = |V_2| = |V_3| = 1$ and $langle V_1, V_2rangle = langle V_1, V_3rangle = langle V_2, V_3rangle = 0$.
    – mechanodroid
    Jul 22 at 23:39
















  • Thanks for the verification and for finding the mistake.
    – philip
    Jul 22 at 23:00










  • then how to verify if I had $V_1,V_2,V_3$
    – philip
    Jul 22 at 23:31










  • @philip $|V_1| = |V_2| = |V_3| = 1$ and $langle V_1, V_2rangle = langle V_1, V_3rangle = langle V_2, V_3rangle = 0$.
    – mechanodroid
    Jul 22 at 23:39















Thanks for the verification and for finding the mistake.
– philip
Jul 22 at 23:00




Thanks for the verification and for finding the mistake.
– philip
Jul 22 at 23:00












then how to verify if I had $V_1,V_2,V_3$
– philip
Jul 22 at 23:31




then how to verify if I had $V_1,V_2,V_3$
– philip
Jul 22 at 23:31












@philip $|V_1| = |V_2| = |V_3| = 1$ and $langle V_1, V_2rangle = langle V_1, V_3rangle = langle V_2, V_3rangle = 0$.
– mechanodroid
Jul 22 at 23:39




@philip $|V_1| = |V_2| = |V_3| = 1$ and $langle V_1, V_2rangle = langle V_1, V_3rangle = langle V_2, V_3rangle = 0$.
– mechanodroid
Jul 22 at 23:39












 

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