Wed July 25, 2012 By:

How to know in which direction is cos component ad in which direction is sin component to the resultant vector?

Expert Reply
Wed July 25, 2012
Suppose there is a vector which makes an angle of "a" with the x-axis, then as it can be seen from the diagram, that if we drop a projection from the end of the vector to x axis, then it will make a right angle triangle and now we can apply relations of trigonometry that:
sin = perpendicular/hypotenuse
cos = base/hypotenuse
Hence in triangle OAA'
OA = A
OA' = A cos(A)
AA' = A sin(A)
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