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If y=sin θ (theta), what is cos θ in terms of y?
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Use Pythagorean identity to answer this question:
`sin^2(theta) + cos^2(theta) = 1`
Plug in `sin(theta) = y:`
`y^2 + cos^2(theta) = 1`
` cos^2(theta) = 1-y^2`
`cos(theta) = +-sqrt(1 - y^2)`
Posted by ishpiro on September 30, 2013 at 4:23 PM (Answer #1)
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