I'm given cos(x) = sq. root(15^2 - 8^2 ) / 15 = sq. root(161) / 15 .
I understand the top part; it is the pythagorean theorem, but why do we divide by 15 afterwards?
I understand the top part; it is the pythagorean theorem, but why do we divide by 15 afterwards?
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Since cos = adj/hyp, and sqrt(161) is the adjacent side to the angle arcsin(8/15)
in an 8, sqrt(161), 15 right triangle.
in an 8, sqrt(161), 15 right triangle.
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because sin x = 8/15 ---> cosx = (sqrt 161)/15