SOLUTION: evaluate wihout wsing a calcuator. cot60

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Question 32560: evaluate wihout wsing a calcuator. cot60
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
Draw a right triangle with acute angles of 30 degrees and 60 degrees.
Let the side opposite the 30 degree angle have length "1"
Then the hypotenuse will have a length of "2".
Then, using Pythagoras, the third side will be sqrt 3
The Cosine of an angle is (adjacent)/(hypotenuse)
The side adjacent to the 60 degree angle is "1".
So the Cos 60 degrees is 1/2
Cheers,
Stan H.