Incorrect Sign In Trigonometric Integral Problem

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SUMMARY

The discussion centers on the integration of the function sin(x)3cos(x)3. The user arrives at the expression {(cos(x))6 / 6} - {(cos(x))4 / 4} while Wolfram Alpha provides -{(cos(x))6 / 6} - {(cos(x))4 / 4}. The discrepancy arises from the inclusion of an arbitrary constant in indefinite integrals, which can lead to different valid forms of the solution. The user acknowledges the omission of the constant of integration, denoted as C, which resolves the inconsistency.

PREREQUISITES
  • Understanding of trigonometric identities, specifically the half-angle formulas.
  • Familiarity with the concept of indefinite integrals and the role of integration constants.
  • Basic knowledge of calculus, particularly integration techniques.
  • Experience with computational tools like Wolfram Alpha for verifying mathematical solutions.
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  • Review the half-angle formulas for trigonometric functions.
  • Study the concept of arbitrary constants in indefinite integrals.
  • Practice integrating various trigonometric functions to solidify understanding of integration techniques.
  • Explore the use of Wolfram Alpha for solving integrals and understanding its output.
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Students studying calculus, particularly those focusing on integration techniques, as well as educators seeking to clarify common misconceptions about indefinite integrals and constants of integration.

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Homework Statement


I am integrating [itex]sin(x)^3cos(x)^3[/itex], I know the technique (I hope) and I get the right equation at the end. But if I ask wolfram alpha what the integral of the equation is and enter 0 into wolfram's answer and also enter 0 into my answer, the answers come out different.

If I change the sign of my first term to negative, the answers come out the same.

So essentially I am getting:

[itex]{(cos(x))^6\over 6} - {(cos(x))^4\over 4}[/itex]

While according to Wolfram Alpha I should be getting:

[itex]-{(cos(x))^6\over 6} - {(cos(x))^4\over 4}[/itex]


Where am I going wrong?

The Attempt at a Solution


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Unfortunately, you can't just plug in numbers to validate your solution. As you probably know, there are an infinite number of constants you can add to have a valid indefinite integral. If you looked on wolfram, the answer it gives has different parameters inside of the cosines. If you repeatedly apply the appropriate half angle formula, it will create more constants to throw into the overall constant. I wouldn't recommend doing this. From what I've seen though, your answer looks fine.
 
gb7nash said:
Unfortunately, you can't just plug in numbers to validate your solution. As you probably know, there are an infinite number of constants you can add to have a valid indefinite integral. If you looked on wolfram, the answer it gives has different parameters inside of the cosines. If you repeatedly apply the appropriate half angle formula, it will create more constants to throw into the overall constant. I wouldn't recommend doing this. From what I've seen though, your answer looks fine.

Ahh... of course, I forgot the C :)

Thank you!
 

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