Prove an odd function is strictly increasing

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An odd function f: R->R satisfies f(-x) = -f(x) for all x. To prove that f is strictly increasing over the entire real line, it suffices to show that it is strictly increasing on the interval [0, ∞). If f is strictly increasing on this interval, then for any u, v in R where u < v, it follows that f(v) - f(u) > 0. The continuity of f and its behavior on (-∞, 0) can be analyzed to confirm that the function remains strictly increasing across the entire domain. Thus, if f is odd and strictly increasing on [0, ∞), it is strictly increasing on R.
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f:R->R is odd, if f(-x)=-f(x) for all x
Show if f:R->R is odd and the restriction of this function to the interval [0, infinity) is strictly increasing
Then f:R->R itself is strictly increasing

I’m very confused about what the question is exactly asking for. From my understanding of the question is that I have any odd function and the graph is strictly increasing in the first quadratic . I need to prove entire graph of such odd function is strictly increasing? Am I interpreting it correctly?
I know how to prove for a strictly increasing function. Let u, v in R, find f(v)-f(u)>0, then f:R->R is strictly increasing function.

Proof:
Given f is an odd function and f is strictly increasing in [0, infinity)
Then f(D) = I, the image of the function is an interval
Therefore f is continuous and strictly increasing?
 
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Just examine the behavior of the function on the interval (-\infty, 0).
 
Okay, got it!
 
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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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