What does this vector equal to?

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In summary, a vector is a mathematical quantity that has both magnitude and direction, commonly represented by an arrow. Its magnitude can be found using the Pythagorean theorem or by calculating the distance between its initial and terminal points. A vector differs from a scalar in that it has both magnitude and direction, while a scalar only has magnitude. Vectors can be added or subtracted by breaking them down into components and finding the resultant vector using the Pythagorean theorem and trigonometric functions. Vectors can also be multiplied, either by a scalar resulting in a vector with a different magnitude, or by another vector resulting in a scalar or vector depending on the method of multiplication.
  • #1
Cuisine123
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Homework Statement


Prove that |[tex]\vec{A}[/tex]|2+|[tex]\vec{B}[/tex]|2 equals to [tex]\frac{1}{2}[/tex](|[tex]\vec{A}[/tex]+[tex]\vec {B}[/tex]|2+|[tex]\vec{A}[/tex]-[tex]\vec{B}[/tex]|2)

Homework Equations


Perhaps the triangle inequality? I am not sure.

The Attempt at a Solution


I have no idea how to approach this question. Please help me with clear explanations. Thank you.
 
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  • #2
Hi Cuisine123! :smile:

Use the definition of modulus: |A + B|2 = (A + B).(A + B) etc :wink:
 
  • #3
Perhaps not the triangle inequality. That is an inequality. You are looking for an equality.

Have you tried expanding the right hand side?
 

1. What is a vector?

A vector is a mathematical quantity that has both magnitude and direction. It is typically represented by an arrow, with the length of the arrow representing the magnitude and the direction of the arrow representing the direction. Vectors are used to represent physical quantities such as velocity, force, and displacement.

2. How do you find the magnitude of a vector?

The magnitude of a vector can be found by using the Pythagorean theorem, where the magnitude is equal to the square root of the sum of the squares of its components. Alternatively, the magnitude can be found by calculating the distance from the initial point to the terminal point of the vector.

3. What is the difference between a vector and a scalar?

A vector has both magnitude and direction, while a scalar only has magnitude. Scalars can be represented by a single number, while vectors require both magnitude and direction to be fully described.

4. How do you add or subtract vectors?

To add or subtract vectors, you must first break them down into their components. Then, add or subtract the corresponding components to get the resultant vector. The magnitude of the resultant vector can be found using the Pythagorean theorem, and the direction can be found using trigonometric functions.

5. Can vectors be multiplied?

Yes, vectors can be multiplied in two ways: scalar multiplication and vector multiplication. Scalar multiplication involves multiplying a vector by a scalar (a number), resulting in a vector with a different magnitude but the same direction. Vector multiplication can take on different forms, such as the dot product and the cross product, and results in a scalar or a vector, respectively.

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