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TS EAMCET · Maths · Vector Algebra

If two vectors \(\vec{a}\) and \(\vec{b}\) which are perpendicular to each other are such that \(|\vec{a}|=8\) and \(|\vec{b}|=3\), then \(|\vec{a}-2 \vec{b}|=\)

  1. A \(10\)
  2. B \(2\)
  3. C \(6\)
  4. D \(12\)
Verified Solution

Answer & Solution

Correct Answer

(A) \(10\)

Step-by-step Solution

Detailed explanation

\begin{aligned} & |\vec{a}|=8,|\vec{b}|=3 \\ & \vec{a} \cdot \vec{b}=0 \\ & |\vec{a}-2 \vec{b}|^2=(\vec{a}-2 \vec{b}) \cdot(\vec{a}-2 \vec{b}) \\ & =|\vec{a}|^2+4|\vec{b}|^2-4 \vec{a} \cdot \vec{b} \\ & =64+36=100 \\ & \therefore \quad|\vec{a}-2 \vec{b}|=10 \text {. } \\ &…