Calculating Unit Vectors and Angles

In summary, a unit vector is a vector with a magnitude of 1 that points in the same direction as another vector. In this problem, you can find the unit vectors b^ and c^ by dividing the vectors b and c by their respective magnitudes. For part b), you can use the dot product formula to find the angle between vectors a and c.
  • #1
andrew.c
46
0

Homework Statement


Given a=2i+3j+k, b=i+2j+k, c=-i-j+k, calculate;

a)unit vectors b^ and c^ in the directions of b and c respectively.
b)the angle between a and c


Homework Equations


n/a


The Attempt at a Solution


I don't understand a) at all,
but b is just a simple dot product question.


Any ideas for a) ?
 
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  • #2
Do you know what a unit vector is?
 
  • #3
a) For any vector x other than the zero vector 0i + 0j + 0k, the vector 1/|x| * x will be a unit vector with the same direction as x.

b) You didn't ask, but one definition of the dot product of vectors a and b is [tex]a \cdot b = |a||b]| cos \theta[/tex]
where [tex]\theta[/tex] is the angle between the two vectors.
 
  • #4
Thank you both. Tbh, I'm still not entirely sure what a unit vector is though, but I do understand Mark44's formula for calculating. Ta
 
  • #5
A unit vector has a magnitude (or length) of 1 unit. You can normalize any nonzero vector by shrinking it or lengthening it to a vector with the same direction, and magnitude 1.
 

FAQ: Calculating Unit Vectors and Angles

How do you calculate the magnitude of a vector?

The magnitude of a vector is calculated by taking the square root of the sum of the squares of its components. This can be represented mathematically as √(x² + y² + z²), where x, y, and z are the components of the vector in the x, y, and z directions, respectively.

What is the purpose of unit vectors?

Unit vectors are used to represent direction and orientation in a vector space. They have a magnitude of 1 and are used to scale other vectors in order to find their components in a given direction.

How do you calculate the dot product of two vectors?

The dot product of two vectors is calculated by multiplying their corresponding components and then summing the results. This can be represented mathematically as a·b = ax * bx + ay * by + az * bz, where a and b are the two vectors and ax, ay, az and bx, by, bz are their components in the x, y, and z directions, respectively.

What is the difference between a unit vector and a regular vector?

A unit vector has a magnitude of 1, while a regular vector can have any magnitude. Unit vectors are used to represent direction and are often used in calculations involving other vectors.

How do you find the angle between two vectors?

The angle between two vectors can be found by using the dot product formula and the magnitude formula. The angle between two vectors a and b can be represented as θ = cos⁻¹((a·b)/(|a||b|)), where |a| and |b| are the magnitudes of the two vectors.

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