Multivariable Calculus - Scalar projection

In summary, the scalar projection of vector b onto vector a is -10/(sqrt(26)) and this is obtained by dividing the dot product of the two vectors by the magnitude of vector a. This is based on the formula for calculating scalar projection, which is |b|*cos(theta) where theta is the angle between a and b. The dot product, which is (a.b)=|a||b|cos(theta), is used to find the angle between the two vectors and then dividing it by the magnitude of vector a gives us the scalar projection.
  • #1
Larrytsai
228
0

Homework Statement


Find the scalar and vector projection of the vector b=(3,5,3) onto the vector a=(0,1,-5) .


Homework Equations





The Attempt at a Solution



What I've tried is multiplying all the i's and j's and k's together and adding up everything because you get a scalar answer in the end so basically...

3*0 + 1*5 + 3*(-5)
= -10
then i tried to divide by the magnitude of vector |a|

|a|=sqrt(26)

so i get scalar projection as -10/(sqrt(26)) as my answer
 
Physics news on Phys.org
  • #2
Ok, so the scalar projection is b.a/|a|. That seems ok. What's your question?
 
  • #3
Can you please explain why we divide by the magnitude of vector "a" and if my work is correct or not please?
 
  • #4
Larrytsai said:
Can you please explain why we divide by the magnitude of vector "a" and if my work is correct or not please?

The scalar projection should be |b|*cos(theta) where theta is the angle between a and b. Since the dot product is given by (a.b)=|a||b|cos(theta) the scalar projection should be (a.b)/|a|. Yes, you are doing fine so far.
 

Related to Multivariable Calculus - Scalar projection

What is multivariable calculus?

Multivariable calculus is a branch of mathematics that deals with the study of functions and their derivatives in multiple dimensions. It involves the use of vector calculus to solve problems in fields such as physics, engineering, and economics.

What is scalar projection in multivariable calculus?

Scalar projection is a mathematical concept that refers to finding the component of a vector in a particular direction. In multivariable calculus, it is used to determine the magnitude of the projection of a vector onto another vector.

How is scalar projection calculated?

The scalar projection of a vector A onto a vector B is calculated by taking the dot product of A and the unit vector in the direction of B. This can be represented as A · (B/|B|), where |B| is the magnitude of B. The result is a scalar value representing the length of the projection of A onto B.

What is the significance of scalar projection in multivariable calculus?

Scalar projection is important in multivariable calculus as it allows us to break down a vector into its components and analyze its behavior in different directions. It also has many applications in physics and engineering, such as calculating the work done by a force in a particular direction.

How is scalar projection used in real-world problems?

Scalar projection is used in a variety of real-world problems, such as finding the shortest distance between two points, determining the angle between two vectors, and calculating the work done by a force in a particular direction. It is also used in optimization problems to find the minimum or maximum values of a function in multiple dimensions.

Similar threads

Replies
9
Views
802
  • Calculus and Beyond Homework Help
Replies
5
Views
2K
  • Calculus and Beyond Homework Help
Replies
9
Views
860
  • General Math
Replies
1
Views
749
  • Calculus and Beyond Homework Help
Replies
20
Views
577
  • Calculus and Beyond Homework Help
Replies
16
Views
1K
  • Calculus and Beyond Homework Help
Replies
3
Views
2K
  • Calculus and Beyond Homework Help
Replies
4
Views
1K
  • Calculus and Beyond Homework Help
Replies
2
Views
2K
  • Calculus and Beyond Homework Help
Replies
2
Views
2K
Back
Top