If a → and b → are unit vectors making an angle α with each other, such that α ∈ 0 , π and a → + 2 b → 5 , then α lies in the interval

Question

If a → and b → are unit vectors making an angle α with each other, such that α ∈ 0 , π and a → + 2 b → 5 , then α lies in the interval, 0 , π, 0 , π 2, π 2 , 2 π 3, π 6 , 5 π 6

MARKS App · Accepted Answer

a → + 2 b → 5 ⇒ a → + 2 b → 2 25 ⇒ a → 2 + 4 b → 2 + 4 a → ⋅ b → 25 ⇒ 1 + 4 + 4 cos ⁡ α 25 ⇒ cos ⁡ α 5 ⇒ α ∈ 0 , π

Search any question & find its solution

Looking for more such questions to practice?