Complex Analysis Entire Functions

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An entire function f(z) that satisfies |f(z)| ≤ R for |z| = R implies that all derivatives at zero, f''(0), f'''(0), and higher, are equal to zero. Consequently, this leads to the conclusion that f(0) must also be zero. Two examples of such functions include the zero function and the function f(z) = e^(-z^2), both of which meet the given conditions. The discussion emphasizes the implications of the growth restrictions on entire functions and their derivatives. Overall, the properties of entire functions are crucial in understanding their behavior at the origin.
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Let f(z) be an entire function such that |f(z)| less that or equal to R whenever R>0 and |z|=R.

(a)Show that f''(0)=0=f'''(0)=f''''(0)=...

(b)Show that f(0)=0.

(c) Give two example of such a function f.
 
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Hint: look back through your old post history. I already explained one tool you could use to approach these problems.
 
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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