Question

Direction cosines of the \(x\)-axis are:

• A. (1, 0, 0)
• B. (0, 1, 0)
• C. (0, 0, 1)
• D. (0, 0, 0)

Hint:

The x-axis makes 0 degrees with itself and 90 degrees with the y- and z-axes.

Answer 1

The Correct Option is A

Step 1: Represent the x-axis as a unit vector:
The x-axis direction is $\hat i=(1,0,0)$, already a unit vector.

Step 2: Direction cosines of a unit vector are its own components:
For a unit vector $(l,m,n)$, the direction cosines are exactly $l,m,n$ themselves.

Final Answer:
\[ \boxed{(1,0,0)} \]