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I have a little thing to ask you that when you plot a graph in linear programming how do you know what scales (or measures) to choose on x-axis and y-axis?
I watched your lecture but was unable to understand this. And I know that drawing the graph will not be asked in the exam
You choose scales such that it will be possible to draw all of the relevant lines (and I do explain this in my lecture).
However, it is irrelevant for the exam since you will never be expected to draw the graph.
BUT how should we actually choose scales to draw all the lines?
According to the example of the notes then we should choose the scale in two ways:
1) Use scales after finding the values for S and E such as in materials S value is 40 while E value is 20. So we should choose a scale up to 40 which is the highest value. (correct?)
2) We can use the average of total available resources such as 80 kg of material is available so choosing the scale would be on average of total available resource (80 kg / 2) = 40 which will be the highest scale.
(Both ways are correct?)
I know that we’ll not be asked to draw in the exam but I am learning to draw myself and I am stuck plotting the scales.
Thanks for your previous answer 🙂
You just need to make sure that the scales go far enough so as to be able to draw all of the lines. So for each constraint put 0 for one of the variables and calculate the value of the other variable, then repeat it putting 0 for the other variable.