Question

If `overline (a) =10hat("i") + lambda hat("j") + 2hat("k")` is perpendicular to `overline (b)= hat ("i")+hat("j")-hat("k")`, then λ is equal to ______.

विकल्प

• 3

• -5

• 7

• -8

Answer 1

If `overline (a) =10hat("i") + lambda hat("j") + 2hat("k")` is perpendicular to `overline (b)= hat ("i")+hat("j")-hat("k")`, then λ is equal to -8.

Explanation:

`overline (a) * overline (b) = 0`

`=> (10hat("i")+lambda hat("j")+2 hat("k")) * (hat("i")+hat("j")-hat("k"))=0`

⇒ 10(1) +(λ) (1) + (2) (-1) = 0

⇒ λ = -8