Question

When the resolution of vectors is done, for example when vector R is resolved into Rsin@ and Rcos@ then, what quantity does Rsin@ and Rcos@ refer to, scalar or vector?

Answer 1

vector

Answer 2

agree. you end up getting:
R=(Rcos@)i+(Rsin@)j
where i and j are unit vectors in the directions of your perpendicular coordinate axes and @ is the angle R makes with one of your unit vectors.

Answer 3

Right, so sin@ and cos@ are always scalar values, by very definition. However, a broken-down vector must have components that are themselves vectors, these being along the x- and y-axis. Usually, those vector components--like Rsin@ and Rcos@--are indicated, like eseidl stated, with unit vector notation of i, j, and k (for x-, y-, and z-axis, respectively). However, if you begin to use inclined planes (such as in Lecture 24), then Rsin@ might be along the slope of the inclined plane, and Rcos@ might be perpendicular to the plane. I hope this helps rather than confuses! Good luck!