Back to The dot product

Exercise 2

Avg difficulty 2.5

Consider the three vectors u=[1−22],v=[111],w=[02−1].\uvec = \threevec1{-2}2, \hspace{24pt} \vvec = \threevec111, \hspace{24pt} \wvec = \threevec02{-1}.

  1. Find the dot products u⋅u\uvec\cdot\uvec, u⋅v\uvec\cdot\vvec, and u⋅w\uvec\cdot\wvec.

  2. Use the dot products you just found to evaluate:

    1. ∣u∣\len{\uvec}.

    2. (−5u)⋅v(-5\uvec)\cdot\vvec.

    3. u⋅(−3v+2w)\uvec\cdot(-3\vvec+2\wvec).

    4. ∣1∣u∣u∣\len{\frac1{\len{\uvec}} \uvec}.

  3. For what value of kk is u\uvec orthogonal to kv+5wk\vvec+5\wvec?

Austin, Understanding Linear Algebra, §6.1 The dot product, Exercise 2

AI Tutor

Adapted from Understanding Linear Algebra © 2023 David Austin. Licensed under CC BY 4.0. Source: Understanding Linear Algebra. Imported at revision 3e6dced.