Question

\(\vec i\cdot\vec i=\) ?

• A. \(0\)
• B. \(1\)
• C. \(-1\)
• D. \(\vec j\)

Hint:

$\vec i\cdot\vec i=\vec j\cdot\vec j=\vec k\cdot\vec k=1$; mixed pairs are \(0\).

Answer 1

The Correct Option is B

Unit vectors have length \(1\) and are mutually perpendicular. Dot product of a vector with itself equals the square of its length: \[ \vec i\cdot\vec i=\|\vec i\|^{2}=1^{2}=1. \]