Problem 17 of 7
Use the Pythagorean identity to find cosine when sin(theta)=3/5 and theta is in Quadrant I.
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solve cos^2(theta)=1-sin^2(theta).
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Sine value must be in [-1,1] and quadrant must determine cosine sign.
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Solution
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1. Use cos^2(theta)=1-sin^2(theta).
2. Take the square root of the remaining value.
3. Choose the sign of cosine from the quadrant.
Use the worked steps, then substitute the final answer back into the original relationship to confirm it satisfies the prompt.
Giving both positive and negative values when quadrant is specified.