- #36
Nugatory
Mentor
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Adel Makram said:I made the following mistake: I used ##\phi=\pi+\alpha## (which is right and I don't know how a writing mistake gave the correct answer later on) instead of ##\phi=\pi-\alpha## and I reached to the correct ##sin^2(\beta-\alpha)##.
##\alpha-\pi##, ##\pi+\alpha##, and "exactly opposite to ##\alpha##" are three different ways of describing the same direction, so of course you get the same result.
If you're facing northeast and you turn ##\pi## radians to the left, or ##\pi## radians to the right, or turn around and look in the opposite direction... you'll be facing southwest.