Derivative of a Complex Function: Finding f'(1 + i)

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To find f'(1 + i) for the function f(z) = (3e^(2z−i)e^(-z))/(z^2−1+i), the correct approach is to differentiate with respect to z first and then substitute (1 + i) into the derivative. It is important to note that "i" is a constant and cannot be treated as a variable during differentiation. This method ensures accurate results in complex function analysis. Proper differentiation techniques are essential for evaluating derivatives at specific points in complex functions.
nickolas2730
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1. Let f(z) = (3e2z−ie-z)/(z2−1+i) . Find f′(1 + i).


3. Should I sub (1+i) to z and then diff it by i.
Or i need to diff it by z first then sub (1+i) in it at last?

Thanks
 
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Welcome to PF, nickolas2730! :smile:

You need to diff it by z first then sub (1+i) in it at last.

Btw, you can't diff by "i". It is not a variable but a constant.
 
thank you so much!
 
Question: A clock's minute hand has length 4 and its hour hand has length 3. What is the distance between the tips at the moment when it is increasing most rapidly?(Putnam Exam Question) Answer: Making assumption that both the hands moves at constant angular velocities, the answer is ## \sqrt{7} .## But don't you think this assumption is somewhat doubtful and wrong?

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