Derivative in the complex plane

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SUMMARY

The discussion focuses on the differentiation of the complex function f(z) = 2x^3 + 3iy^2. The user initially calculates the derivative using partial derivatives, yielding f'(x + ix^2) = 6x^2 + 6ix^2. However, this result does not align with the expected derivative of f' = 6x^2 found in the textbook. The discrepancy arises from the incorrect application of partial differentiation instead of utilizing the Cauchy-Riemann equations, which are essential for complex differentiation.

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  • Understanding of complex functions and their representations.
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  • Familiarity with partial derivatives and their application in multivariable calculus.
  • Basic proficiency in complex analysis concepts.
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cragar
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Homework Statement


f(z)=2x^3+3iy^2 then it wants
f '(x+ix^2)

The Attempt at a Solution



So I take the partial with respect to x and i get
6x^2 then partial with respect to y and I get
6iy, then I plug in x for the real part and x-squared for the imaginary part,
then I get f ' (x+ix^2)=6x^2+6ix^2
the back of my book has f' = 6x^2
I don't see why its not what I got.
 
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What do you know about complex differentiation? How is it defined? Which formulas do you know?
If you took the partial differentials, then this is not the complex differential. So why did you use them, i.e. how are they related?
 
I know cauchy reimann formulas, so I did it wrong, first off it doesn't satisfy c-r formulas,
but for the imaginary part I should of taken the partial with respect to x as cauchy reimann implies, then that partial would be zero,
then the derivative would be 6x^2 .
 

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