Chain rule and cylindrical coordinates

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SUMMARY

The discussion focuses on the application of the chain rule in cylindrical coordinates, specifically in the context of differentiating the angle theta defined as theta = tan^-1(y/x). The derivative d theta/d x is derived as y/(x^2 + y^2) by applying the chain rule and treating y as a constant during differentiation. This derivation is essential for understanding how changes in x affect the angle theta in polar coordinates.

PREREQUISITES
  • Understanding of basic calculus concepts, particularly the chain rule.
  • Familiarity with cylindrical coordinates and their mathematical representation.
  • Knowledge of trigonometric functions, specifically arctangent.
  • Ability to differentiate functions with respect to a variable while treating others as constants.
NEXT STEPS
  • Study the chain rule in depth, focusing on its applications in multivariable calculus.
  • Learn about cylindrical coordinates and their transformations from Cartesian coordinates.
  • Explore differentiation of inverse trigonometric functions, particularly arctan.
  • Practice problems involving derivatives in polar and cylindrical coordinate systems.
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Students and professionals in mathematics, physics, and engineering who are looking to deepen their understanding of calculus, particularly in the context of cylindrical coordinates and the chain rule.

cycling4life
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I'm trying to understand this one derivation but this one part keeps messing me up;

theta = tan^-1 (y/x)
r^2 = x^2 + y^2

d theta/ d x = y/ (x^2 + y^2) how did they get this line?
 
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You just need to differentiate arctan(y/x) wrt x. Assume y is a constant for the purposes of this integration, of course.
 

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