thank you so much for your help! I was so confused with duality until I watched your whole playlist, and it made me understand the concept well with all cases! Your instruction was very clear.
Respected Sir, Sir I visited numerous coaching centres during my graduation for Mathematics, though I had my honours in Economics, my general paper was Maths and Stats. One thing I couldn't understand was "Duality". None of the teachers was able to explain properly and I was like so much confused. Then I searched TH-cam and found your vedios. I am so grateful to you for making this topic a ' baye haat ka khel ' for me. I can now solve the mixed constraint and unrestricted signs sums within a few minutes. Your are really great...! Thank you again Sir.... Thanks a ton...!
Really like your videos, just a friendly reminder: there is a mistake in the final dual in second constraint. It is y_1+y_2+y' >= 4 and not y_1-y_2+y' >= 4 :)
Thank you Nirmal Kumar. I'll be uploading many more videos on many new topics. Please share these videos with other students through FB pages/groups and let them also get the same benefit... :)
In real life the factors/variables like 'Return on Investment' etc may, naturally, take negative or positive or zero value. Thus, such variable remains unrestricted in sign, at least in the formulated LPP. Non-negativity condition is the necessity of the application of method(s) of solution only and not of the formulation... :)
Thanks a lot but I have more questions. My teacher is super confusing and the exam is tomorrow. Can you please help me with finding optimal solution of an LP model using the vector approach? If you send me your email I will send you the problem that he worked in class so that you can further explain it because it looks like he will bring that same problem on the exam. Thanks
Sir i have observed in comments that people are complaining for small writing mistakes even though you are saying it correct. I would suggest that in future before uploading the video you can edit the part where writing is done wrong by replacing it with digital text, that way you will not have to reshoot the video. Great videos. I have understood everything very clearly. Thank you for making these videos.
Thank you very much, Anurag... Now I have started watching the videos before uploading... The surrounding of my place is always with so much noise that it's too difficult to maintain concentration, and, unfortunately, I am not in a situation to change the place within short period of time. I hope I'll soon reach the level of 'zero defect' with taking extra care... Thanks again... :)
Nice video! One question: Why do you write in 11:19 y1-y2+y'>=4? Dual revised Primal says y1+y2+y'>=4. Where does this - come from? If the - sign is wrong: How can you write an equation which is the same equations as the next one, but the values are different? y1+y2+y'>=4 and y1+y2+y'=7. How can a equation once be =7 and once >=4?
Yes, it should be +y2 and not - y2, this I had commented earlier also. But reading the last part of your comment it seems that you are making some mistake in getting the point. The last two constraints in the dual have same values with exactly reverse signs of the coefficients, this is because they are two inequality-parts of the single equality. To understand this refer to the beginning of the same solution where we split the equality in the primal into two inequalities with reverse signs. At the end in the dual we need to write an equality in the place of the two inequalities having reverse signs...
Yes, it is a writing error... but I didn't prefer to re-shoot the whole lecture for this little error which has, ultimately, no effect on the further process and the final solution. I am sorry, if you faced any inconvenience... and thank you for the reminder...:)
sir, your insightful and hands-on treatment of the subject made the topic very lively. We are deeply indebted for uploading this video. Can you do some videos on DEA and Use of DEA concepts to solve institutional efficiency problems with some case studies
Sir i have problem in which objective function has 2 variables subjected to 2 constraints which contain 3 variables 2 are unrestricted how we solve that?
Thank you Ritu, Yes, I have uploaded videos on Big-M Method. There is a playlist of 'Big-M Method' on my TH-cam channel "Prashant Puaar". I hope all the videos would be proved very useful to you. :)
Dear sir, In this problem, if we take all constraints with 'greater than or equal to' except equal sign(in third constraint) in its dual, can we do such ?
We cannot decide or pre-plan the signs of inequalities in the dual. They can only be according to the objective of the dual and number of unrestricted variables in the primal... :)
No sir , I am asking that you taken equal sign in third constraint ( in dual) , can we keep all constraints with 'greater than or equal to' sign in dual
But why??? When you have a variable unrestricted in sign at number 3 in the primal, in its dual there must come a constraint in the form of equality (=) at number three. I have already explained these rules...
The meaning of the non-negativity constraint is "zero or greater than zero (i.e zero or positive)"... So, now you just think how can there be "less than" sign in non-negativity constraint... :)
It is 'variable' which can be 'unrestricted in sign' and not the constraint... In the same way but everything should be done simultaneously for both the "unrestricted variables'...
sir if i get similar between y2 and y3 in some other question can i replace it with y' and get answer wirh y1,y' and y4 sir ive send u a solution(pic) in ur facebook page can u plz check it ,is it wrong or right??plzzzzz help
In this case your second constraint is an equality and, as a result, you will get the 'unrestricted' variable at the same, i.e. second, place in the dual. Similarly you will get an equality as a constraint at the same place in the dual as in the primal there is an 'unrestricted' variable. You can learn all such things in the videos also, as Ihave discussed these things on different lectures on duality... :)
Thanks you! Keep watching keep learning... Visit and subscribe my channel and don't forget to recommend my channel and lectures/playlists to others also... you will find so many subjects/topics... :)
Thanks and Welcome... Keep watching, keep learning... Please don't forget to like and share and also recommend my channel th-cam.com/channels/qedkv6AYxh3hk99EPtGlmQ.html to the others...
![LPP - Graphical Method [#2] [Minimization & Maximization with 3 Constraints] :-by kauserwise](/img/n.gif)
thank you so much for your help! I was so confused with duality until I watched your whole playlist, and it made me understand the concept well with all cases! Your instruction was very clear.
Respected Sir,
Sir I visited numerous coaching centres during my graduation for Mathematics, though I had my honours in Economics, my general paper was Maths and Stats. One thing I couldn't understand was "Duality". None of the teachers was able to explain properly and I was like so much confused. Then I searched TH-cam and found your vedios.
I am so grateful to you for making this topic a ' baye haat ka khel ' for me.
I can now solve the mixed constraint and unrestricted signs sums within a few minutes.
Your are really great...!
Thank you again Sir.... Thanks a ton...!
Really like your videos, just a friendly reminder: there is a mistake in the final dual in second constraint. It is y_1+y_2+y' >= 4 and not y_1-y_2+y' >= 4 :)
Campovski just about to write it :)
hats off to you sir .....u have the best teaching method for topics like these .....am very thankful to you....
You're basically teaching me this course at this point lol, thank you!
You are welcome...:)
saaammmmmmeeeeeeeeee
Thanks a lot Sir, for uploading the series of videos for Duality. All the videos are sequential and highly informative. Thank you once again.
Thank you Nirmal Kumar. I'll be uploading many more videos on many new topics. Please share these videos with other students through FB pages/groups and let them also get the same benefit... :)
Yeah., sure Sir.
Why is X3 unrestricted in sign?
In real life the factors/variables like 'Return on Investment' etc may, naturally, take negative or positive or zero value. Thus, such variable remains unrestricted in sign, at least in the formulated LPP. Non-negativity condition is the necessity of the application of method(s) of solution only and not of the formulation... :)
Thanks a lot but I have more questions. My teacher is super confusing and the exam is tomorrow. Can you please help me with finding optimal solution of an LP model using the vector approach? If you send me your email I will send you the problem that he worked in class so that you can further explain it because it looks like he will bring that same problem on the exam. Thanks
Best teacher all cases covered
it was much needed for operations. it cleared the concept. thankyou
Thank you very much sir for providing such helpful video... this will help for examination time confusion clearance. Thanks.
Sir i have observed in comments that people are complaining for small writing mistakes even though you are saying it correct. I would suggest that in future before uploading the video you can edit the part where writing is done wrong by replacing it with digital text, that way you will not have to reshoot the video.
Great videos. I have understood everything very clearly. Thank you for making these videos.
Thank you very much, Anurag...
Now I have started watching the videos before uploading... The surrounding of my place is always with so much noise that it's too difficult to maintain concentration, and, unfortunately, I am not in a situation to change the place within short period of time. I hope I'll soon reach the level of 'zero defect' with taking extra care... Thanks again... :)
Thank you for your time and efforts Sir!
Good concept clearity... But in final dual 2nd constraint has a little mistake of + sign
sir, you cleared all my doubts thank you so much .. god bless you
Nice video! One question: Why do you write in 11:19 y1-y2+y'>=4? Dual revised Primal says y1+y2+y'>=4. Where does this - come from? If the - sign is wrong: How can you write an equation which is the same equations as the next one, but the values are different? y1+y2+y'>=4 and y1+y2+y'=7. How can a equation once be =7 and once >=4?
Yes, it should be +y2 and not - y2, this I had commented earlier also. But reading the last part of your comment it seems that you are making some mistake in getting the point. The last two constraints in the dual have same values with exactly reverse signs of the coefficients, this is because they are two inequality-parts of the single equality. To understand this refer to the beginning of the same solution where we split the equality in the primal into two inequalities with reverse signs. At the end in the dual we need to write an equality in the place of the two inequalities having reverse signs...
Prashant Puaar Nice, thanks a lot!
Hi Profesor,
thank you very much for the explanation,
just one question, Why the sign of the y' (y dashed) is positive?
something is wrong...x4 and x5 should be >=0 not 5
Yes, it is a writing error... but I didn't prefer to re-shoot the whole lecture for this little error which has, ultimately, no effect on the further process and the final solution. I am sorry, if you faced any inconvenience... and thank you for the reminder...:)
it happens n problem thankyou so much
Awesome sir! U save our lives 👍🏼👍🏼 thank u!!
... :) :)
sir, your insightful and hands-on treatment of the subject made the topic very lively. We are deeply indebted for uploading this video. Can you do some videos on DEA and Use of DEA concepts to solve institutional efficiency problems with some case studies
Sir i have problem in which objective function has 2 variables subjected to 2 constraints which contain 3 variables 2 are unrestricted how we solve that?
So nice job sir thanks a lot
sir, i would like to ask what if there are two urs ? e.g: X2,X3 urs can i use X2 = X3 = X4 - X5 ?? thank you.
this was good. do you have a video on big m method?
Thank you Ritu,
Yes, I have uploaded videos on Big-M Method. There is a playlist of 'Big-M Method' on my TH-cam channel "Prashant Puaar". I hope all the videos would be proved very useful to you. :)
thank u sir for such a easy way of explanation
Thanks sir for your precious knowledge .
amazing explanation sir
very well explained... 😊
very helpful...thanku so much sir
Thank you so much sir,but sir u have written greater than equal to 5 (X4-X5) mistakenly but its ok,teaching style is just wao loved it.
Thank you very much, this was helpful!
You are Welcome... :)
Dear sir, In this problem, if we take all constraints with 'greater than or equal to' except equal sign(in third constraint) in its dual, can we do such ?
We cannot decide or pre-plan the signs of inequalities in the dual. They can only be according to the objective of the dual and number of unrestricted variables in the primal... :)
No sir , I am asking that you taken equal sign in third constraint ( in dual) , can we keep all constraints with 'greater than or equal to' sign in dual
But why??? When you have a variable unrestricted in sign at number 3 in the primal, in its dual there must come a constraint in the form of equality (=) at number three. I have already explained these rules...
Ok sir ,, got it
thank you very much sir. This is very helpful
excellent explanation , thnk u sir
God bless you good sir.
Sir, if there is less than sign in non negative constraints???
The meaning of the non-negativity constraint is "zero or greater than zero (i.e zero or positive)"... So, now you just think how can there be "less than" sign in non-negativity constraint... :)
I'm very thankful to uh... this was helpful
Sir agr question minimize ka ho r sary constrain less ky ho to us ka dual kesy bny ga r solution k lye kn sa method use kry gy
If all the signs are 'less than or equal to", then why should we form its dual? We can solve it directly through Simplex Method.
Thank u sir
thanks a lot sir you made the day
thank you very much
Sir, how to do it when two constraints are unrestricted
It is 'variable' which can be 'unrestricted in sign' and not the constraint...
In the same way but everything should be done simultaneously for both the "unrestricted variables'...
the sign of y2 in final dual is wrong
thank u so much for this video
Thank you so much teacher
thank u sir i understand clearly ...
great video
Thank you sir.... 👏
sir ive a doubt
in final dual in 2nd equation y r u writing y1-y2+y'>=4...............y not y1+y2+y'>=4........................?????plz rpl soon
Yes, Priya, You are right. It should be +y2 and not - y2.
thnx a lot sir :)
grt work
sir if i get similar between y2 and y3 in some other question can i replace it with y' and get answer wirh y1,y' and y4
sir ive send u a solution(pic) in ur facebook page can u plz check it ,is it wrong or right??plzzzzz help
In this case your second constraint is an equality and, as a result, you will get the 'unrestricted' variable at the same, i.e. second, place in the dual. Similarly you will get an equality as a constraint at the same place in the dual as in the primal there is an 'unrestricted' variable. You can learn all such things in the videos also, as Ihave discussed these things on different lectures on duality... :)
think you very much.
Thank you Sir.
Very helpful, thank you so much sir
thanku for explaine
Excellent
Thanks you! Keep watching keep learning... Visit and subscribe my channel and don't forget to recommend my channel and lectures/playlists to others also... you will find so many subjects/topics... :)
thank you sir!!!
Thanks
Please give me your Divine blessings
Sir plz do a video on cutting plane method and branch and bound method plz
Perfect thank u
Thanks and Welcome...
Keep watching, keep learning...
Please don't forget to like and share and also recommend my channel th-cam.com/channels/qedkv6AYxh3hk99EPtGlmQ.html to the others...
oh this saved my life. Engineering succckkksss. :3
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