SM 025_VECTOR_Basic 2

Show that the vectors a = i + 2j + k, b = –2i + j – 3k  and c = i – 3j + 2k  construct a triangle

• If the vectors form a triangle, then the

  sum of the three vectors is 0

• If the vectors form a triangle, then the

  sum of the three vectors is 1

• If the vectors form a triangle, then the

  sum of the three vectors is 90'

• If the vectors form a triangle, then the

  sum of the three vectors is 180'

Given the vectors a = 2i + j + 3k and b = –i + j + k, find 2b . a

• 5

• 4

• 6

• 7

Answer explanation

)   2b . a =

2(-i + j + k).(2i + j + 3k)

                            

=  4

Given the vectors a = 2i + j + 3k and b = –i + j + k, find )  the angle between a and b.

Answer explanation

Given that a = 2i – 3j + k and b = i – 4j + 5k, find a x (a x b)

• =  2i -5 j - 1k

• =  4i - j - 5k

• 24i - j - 51k

• =  51i -2 j - 51k