The Exact Value of sin 22.5 degrees (Alternate Solution) (2 of 5)

The exact value of sin 22.5deg = √(2-√2)/2 can be solve by using the sine function's half-angle formula sin (theta/2) = √{[1 - (cos theta)]/2}, where theta = 45deg, or sin [(45deg)/2] = sin (22.5deg) = √{[1 - (cos 45deg)]/2}. Substitute the exact value of cos 45deg = √2/2 to the formula, in which I've already solved above and included in this playlist. Evaluate and simplify.

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