If a vector is denoted by A then its x-component can be written as

C. Acosθî

The correct answer is:

C. Acosθî

Here’s why:

• A vector can be represented by its magnitude (A) and direction.
• In a rectangular coordinate system, we use unit vectors î for the x-axis and ĵ for the y-axis.
• The x-component of the vector represents the contribution of the vector along the x-axis.
• To denote this contribution, we use the magnitude (A) multiplied by cosine (cos) of the angle (θ) the vector makes with the positive x-axis. Cosine tells us the relative length of the vector projected onto the x-axis.
• Therefore, Acosθî represents the x-component of vector A.

Similarly, A sinθĵ would represent the y-component of vector A.