- . . . floor.1
- By
convention, angles are measured counter-clockwise
from the reference axis, so technically
is negative; this makes no difference to its cosine.
Thus
is initially positive and
is initially negative.
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- . . .
negative.2
- Again the convention is
to treat counter-clockwise rotations as positive;
by inspection we can see that
must be clockwise,
so
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As long as a consistent notation is used,
it doesn't matter if the direction shown is opposite to the
actual direction; the answer will always come out of any
correct calculation with the required minus sign.
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