Surface area of sin(x) rotated about the x-axis

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SUMMARY

The discussion focuses on calculating the surface area of the function sin(x) when rotated about the x-axis. A key point raised is the derivative of 1 + cos²(x), which is correctly identified as -2sin(x)cos(x). The participants suggest using the substitution u = cos(x) to simplify the integration process, which proves to be a more effective approach than the initial substitution attempted.

PREREQUISITES
  • Understanding of calculus, specifically surface area calculations.
  • Familiarity with trigonometric functions and their derivatives.
  • Knowledge of substitution methods in integration.
  • Basic understanding of rotation of curves about the x-axis.
NEXT STEPS
  • Research the method for calculating surface areas of revolution using integrals.
  • Learn about trigonometric identities and their derivatives, particularly for cos²(x).
  • Study substitution techniques in integral calculus, focusing on trigonometric substitutions.
  • Explore examples of surface area calculations for different functions rotated about the x-axis.
USEFUL FOR

Students and educators in mathematics, particularly those studying calculus, as well as professionals needing to apply integration techniques in engineering or physics contexts.

emc92
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got stuck on doing the substitution.. any suggestions?
 

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emc92 said:
got stuck on doing the substitution.. any suggestions?

For one thing, the derivative of 1 + cos2(x) is -2sin(x)cos(x), not -2sin(x).

That substitution doesn't seem to help anyway.

Try u = cos(x) instead.
 
wow, i did not see that.
thanks so much!
 

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