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anonymous

  • 5 years ago

can someone verify that Example 1 on this site has an error? http://tutorial.math.lamar.edu/Classes/CalcI/TrigEquations_CalcII.aspx I think the second angle is suppose to be 1.5344 and not 2.5345

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  1. anonymous
    • 5 years ago
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    How do you figure? 2x - 1 = 2.2143 + 2πn 2x - 1 = 4.0689 + 2πn 2x = 2.2143 + 2πn + 1 = 3.2143 + 2πn 2x = 4.0689 + 2πn + 1 = 5.0689 + 2πn x = (3.2143 + 2πn) / 2 = 1.60715 + πn (mult. both 3.2143 and 2πn by 1/2) x = (5.0689 + 2πn) / 2 = 2.53445 + πn (mult. both 5.0689 and 2πn by 1/2)

  2. anonymous
    • 5 years ago
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    well i got 2x-1 = 2.2143 so i added one first to both side, getting 2x = 3.2143 + 2πn for my first angle. and the second angle would be 2π - 3.2143 = 3.0689 so x = 1.5344 + πn

  3. anonymous
    • 5 years ago
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    Well, if you take the x that you calculated (i.e. 1.5344 + πn) where n = 0, you'll notice that when you put it back into cos(2x - 1) it doesn't equal -3/5. So, your answer is incorrect. And it is probably because you either didn't have your calculator in radians or you took the x you calculated, which by the way is NOT the angle (2x - 1 is) and subtracted 2π from it which will give you an incorrect answer. I checked both the answers for x in the example and they both equate to ≈ -3/5 = -0.6

  4. anonymous
    • 5 years ago
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    you're right, I found my mistake. I changed the angle when I added 1 before calculating for the second angle. Thankss!

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