1. Let v, w be any two vectors. Prove that ||v + w||² - ||v − w||² = 4v. w W (Hint: Use properties of the dot product. Do NOT use component forms of the vectors.)

Linear Algebra: A Modern Introduction
4th Edition
ISBN:9781285463247
Author:David Poole
Publisher:David Poole
Chapter2: Systems Of Linear Equations
Section2.3: Spanning Sets And Linear Independence
Problem 21EQ
icon
Related questions
Question
1. Let v, w be any two vectors. Prove that
||v + w||2 - ||vw||² = 4v • w
W
(Hint: Use properties of the dot product. Do NOT use component forms of the vectors.)
2. Suppose that v, w are orthogonal. Use Equation (1) to show that
||vw|| = ||v + w||.
3. Let x, y be any two vectors. Assume that
||x + y || = |x|| = ||y||
Find the angle between x, y.
(Hint: Begin by squaring both sides of the first equation given above. Alternatively, use
geometry as a guide. Your proof cannot rely on geometry, but it is a strong starting point.)
4. Use the 3-space standard basis vectors to find three nonzero vectors a, b, c satisfying axb =
a x c, where a × b / 0 and b = c.
(This proves that the cross product operation does not have cancellation across equations.)
Transcribed Image Text:1. Let v, w be any two vectors. Prove that ||v + w||2 - ||vw||² = 4v • w W (Hint: Use properties of the dot product. Do NOT use component forms of the vectors.) 2. Suppose that v, w are orthogonal. Use Equation (1) to show that ||vw|| = ||v + w||. 3. Let x, y be any two vectors. Assume that ||x + y || = |x|| = ||y|| Find the angle between x, y. (Hint: Begin by squaring both sides of the first equation given above. Alternatively, use geometry as a guide. Your proof cannot rely on geometry, but it is a strong starting point.) 4. Use the 3-space standard basis vectors to find three nonzero vectors a, b, c satisfying axb = a x c, where a × b / 0 and b = c. (This proves that the cross product operation does not have cancellation across equations.)
Expert Solution
steps

Step by step

Solved in 2 steps

Blurred answer
Recommended textbooks for you
Linear Algebra: A Modern Introduction
Linear Algebra: A Modern Introduction
Algebra
ISBN:
9781285463247
Author:
David Poole
Publisher:
Cengage Learning
Elementary Linear Algebra (MindTap Course List)
Elementary Linear Algebra (MindTap Course List)
Algebra
ISBN:
9781305658004
Author:
Ron Larson
Publisher:
Cengage Learning
Trigonometry (MindTap Course List)
Trigonometry (MindTap Course List)
Trigonometry
ISBN:
9781305652224
Author:
Charles P. McKeague, Mark D. Turner
Publisher:
Cengage Learning
Trigonometry (MindTap Course List)
Trigonometry (MindTap Course List)
Trigonometry
ISBN:
9781337278461
Author:
Ron Larson
Publisher:
Cengage Learning
Algebra & Trigonometry with Analytic Geometry
Algebra & Trigonometry with Analytic Geometry
Algebra
ISBN:
9781133382119
Author:
Swokowski
Publisher:
Cengage