Math Problem Statement

let x, y, z be non zero vectors and suppose w = 15x - 5y - 3z and Z = 3x - y. Using the calculation above, is the span(x,y,z) = span(w,x,z)

Solution

We are given the following vectors:

  • w=15x5y3zw = 15x - 5y - 3z
  • Z=3xyZ = 3x - y

We are tasked with determining if the span of {x,y,z}\{x, y, z\} is equal to the span of {w,x,z}\{w, x, z\}. To do this, we'll check if yy can be expressed as a linear combination of w,x,zw, x, z, because if it can, then the span of {x,y,z}\{x, y, z\} is indeed equal to the span of {w,x,z}\{w, x, z\}.

Step 1: Express yy in terms of w,x,zw, x, z

Start with the expression for ww:

w=15x5y3zw = 15x - 5y - 3z

Solve for yy:

w=15x5y3zw = 15x - 5y - 3z w+5y=15x3zw + 5y = 15x - 3z 5y=15x3zw5y = 15x - 3z - w y=3x35z15wy = 3x - \frac{3}{5}z - \frac{1}{5}w

This shows that yy can indeed be written as a linear combination of w,x,zw, x, z.

Step 2: Conclusion

Since yy can be expressed as a combination of w,x,zw, x, z, it follows that the span of {x,y,z}\{x, y, z\} is the same as the span of {w,x,z}\{w, x, z\}. Therefore:

span(x,y,z)=span(w,x,z)\text{span}(x, y, z) = \text{span}(w, x, z)

Would you like further details or have any questions?

Relative Questions:

  1. What is the geometric interpretation of vector spans?
  2. How do linear combinations relate to the span of a set of vectors?
  3. Can the span of more than three vectors ever equal the span of three vectors?
  4. How does the concept of span apply in higher dimensions, such as R4\mathbb{R}^4?
  5. How can we generalize the relationship between two spans like in this problem?

Tip:

When checking if two spans are equal, express the vectors of one span in terms of the other. If all vectors in one span can be written as combinations of the other set, the spans are equal.

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Math Problem Analysis

Mathematical Concepts

Linear Algebra
Vector Spaces
Spanning Sets
Linear Combinations

Formulas

w = 15x - 5y - 3z
Z = 3x - y
y = 3x - (3/5)z - (1/5)w

Theorems

Linear Independence
Spanning Set Definition
Vector Space Basis

Suitable Grade Level

Undergraduate Linear Algebra