Question

Which of the following are orthogonal to (2, 1)? Check all that apply.

A. (1, 2)
B. (-2, -3)
C. (-3, 6)
D. (1, -2)

Please explain. Thank you!

Answer 1

@jim_thompson5910

Answer 2

Two vectors are orthogonal if and only if their dot product is 0

so u dot v = 0 if and only if u and v are orthogonal factors

Answer 3

u = <a,b>
v = <2,1>

u dot v = a*2 + b*1 = 2a + b = 0

Answer 4

@jim_thompson5910 So then C. (-3,6) and D. (1,-2)

Answer 5

correct on both