If sin Θ = 21/29, use the Pythagorean Identity to find cos Θ. A. cos Θ = ± 8 over 29 B. cos Θ = ± 21 over 20 C. cos Θ = ± 29 over 20 D. cos Θ = ± 20 over 29

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Mathematics

Craig Villa

17 December, 13:29

If sin Θ = 21/29, use the Pythagorean Identity to find cos Θ. A. cos Θ = ± 8 over 29 B. cos Θ = ± 21 over 20 C. cos Θ = ± 29 over 20 D. cos Θ = ± 20 over 29

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Carsen Sellers · Answer 1

If If sin Θ = 21/29, then the y-component should be equal to 21 and the hypotenuse is equal to 29. In this case, using the pythgorean theorem, the x-component is obtained from (29^2-21^2) ^1/2 equal to 20. Hence cos Θ should be + / - 20/29. This has + / - because positive sine can be in quadrant II where cosine value is negative