mahrap said:
a, b, and c are unit vectors and a+b+c=0. This is the first part of a question and the solution involves the fact that a, b, and c form a triangle. I am having a really hard time how these vectors form a triangle. Can you pleases be as thorough as possible in your answer.
What do you think "a+ b+ c" means for vectors? Draw a vector and call it "a". Draw another vector and call it "b". "a+ b" means the tail of vector b is attached to the tip of vector b. "a+ b" is the vector whose tail is at the tail of "a" and whose tip is at the tip of "b". And, the, of course, "a+ b+ c" means we have another vector, "c", whose tail is attached to the vector "b". That sum. "a The "0" vector has no length its "tail" is the same as its "tip". Saying that "a+ b+ c= 0" means that the tail of vector "a" (which is the tail of "a+ b+ c" and the tip of "c" (which is the tip of "a+ b+ c") are the
same point.
That means that the three vectors form a triangle.
Are they unit vectors such as a = <1,0,0> b=<0,1,0> and c=<0,0,1>. But how would that =0?
No, precisely
because they do not add to 0, they add to <1, 1, 1>. But, for example, a= <1/2, 1, 0>, <1/2, -1, 0>, <-1, 0, 0> add to 0 and, geometrically, they form the triangle with vertices at (0, 0, 0), (1/2, 1, 0), and (1, 0, 0).
(Yes, I did that in two dimensions just because it is easier- and a triangle is, after all, a two dimensional figure.)
Thank you so much for all the help.