→                 →                                 →→

a=⟨3,−1⟩, and b=⟨2,2⟩. Represent a+b by using the parallelogram method.

                                                                          →  →

complete the parallelogram method, and draw a +b. 

select the initial point and then the terminal point.


 May 8, 2020

The initial point is (0,0).           [There should be arrows above each of the vector names below.]

Plot the point (3,-1). a is the vector that begins at (0,0) and ends at (3,-1).

Plot the point (2,2). b is the vector that begins at (0,0) and ends at (2,2).


If you add these two vectors together:  a + b  =  (3-1) + (2,2)  =  (5,1).

In either order:                                       b + a  =  (2,2) + (3,-1)  =  (5,1).


You get the same terminal point either way.


The terminal point of  a + b  is  (5,1).

If you draw the vector from (0,0) to (5,-1), you have draw the resultant vector. 

 May 8, 2020

Hello! Im sorry if this seems like a dumb mistake but I am pretty sure I plotted it incorrectly and I am not sure what I did wrong.

Guest May 9, 2020


Thanks Geno,

I think Geno made a small copy error when he told you to plot  (5,-1).  He meant (5,1)


Maybe this will help.


Can you see how vector b has been moved so that it is still the same length and parallel (same direction) but its start point has moved to (3,-1)

This is how vectors are added. It is the pictorial version of what is happening with the numbers.





Melody  May 9, 2020

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