Vectors how are a,b,c in a+b+c=0 a triangle

In summary: This means that the tail of the first vector is the same as the tip of the last vector, creating a triangle. This is true for any three vectors that add up to zero, not just unit vectors.
  • #1
mahrap
37
0
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. Thank you so much for all the help.
 
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  • #2
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.

Are they unit vectors such as a = <1,0,0> b=<0,1,0> and c=<0,0,1>. But how would that =0?

Thank you so much for all the help.
 
  • #3
Unit vectors can be other ones than the a, b, and c in your original post.

If a vector has components vx, vy, and vz, a unit vector is one in which
vx^2+vy^2+vz^2 = 1
 
  • #4
Try adding these vectors graphically, using the head-to-tail method, such that the resultant is a vector with zero magnitude.
 
  • #5
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.
 
  • #6
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.

Are they unit vectors such as a = <1,0,0> b=<0,1,0> and c=<0,0,1>. But how would that =0?

Thank you so much for all the help.

SteamKing said:
Unit vectors can be other ones than the a, b, and c in your original post.

If a vector has components vx, vy, and vz, a unit vector is one in which
vx^2+vy^2+vz^2 = 1
To clarify what SteamKing wrote, he's talking about vx, vy, and vz, the x-, y-, and z-components of a unit vector v.

Regarding the triangle, if the vectors can be arranged, head-to-tail, so that they start and end at the same point, the sum of the vectors is zero.
 

1. What are vectors?

Vectors are mathematical objects that have both magnitude (size) and direction. They are commonly represented by arrows in diagrams.

2. How are vectors typically denoted?

Vectors are typically denoted using boldface letters (e.g. a) or by placing an arrow on top of the letter (e.g. a).

3. What does a+b+c=0 mean in relation to a triangle?

In a triangle, the sum of all three sides (represented by vectors a, b, and c) is equal to 0. This is known as the Triangle Law or Parallelogram Law of Vector Addition.

4. How do you determine the direction of a triangle's third side?

The direction of the third side of a triangle can be determined by using the Triangle Law or Parallelogram Law of Vector Addition. This involves adding the two known sides (vectors a and b) and then finding the negative of that sum (i.e. -a-b). This negative vector represents the opposite direction of the third side (vector c).

5. Can vectors be used to solve problems involving triangles?

Yes, vectors can be used to solve various problems involving triangles such as finding unknown sides or angles, determining the perimeter or area of a triangle, and analyzing the forces acting on an object in a triangular shape. They are a powerful tool in geometry and physics.

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