Final answer:
The student's question involves trigonometric identities to find an expression for the distance from a point to a line. However, none of the options provided correctly represent this in terms of the cosine double angle identities. The correct formula for the distance between a point and a line is not given in the options presented.
Step-by-step explanation:
The student's question is about finding the right expression related to the distance from a point to a line using trigonometric identities, such as the cosine double angle formula. According to the cosine 2θ theorem, we can establish these identities: cos 2θ = cos² θ - sin² θ, cos 2θ = 2cos² θ - 1, and cos 2θ = 1 - 2sin² θ. Considering these identities, none of the student's provided options (a) to e)) correctly represent the formula for the distance between a point and a line in terms of θ and the trigonometric function of a double angle.