A displacement vector R is resolved into rectangular components Rx and Ry along the x- and y-axes respectively.
a. (i) Using a neatly labelled right-angled triangle, explain why the magnitude of R depends only on Rx and Ry. State the relationship obtained.
b. (ii) Describe, with reasoning, how the direction of R with respect to the positive x-axis can be expressed in terms of Rx and Ry for vectors situated in all four quadrants.