Diff EQ Intro - Verify Family of Functions as Solution

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To verify the family of functions as a solution to the differential equation dy/dx + 2xy = 1, one must differentiate y with respect to x and apply the Fundamental Theorem of Calculus to handle the integral. The differentiation yields dy/dx = e^(-x^2) * e^(x^2) - 2x * e^(-x^2) * ∫(from 0 to x) e^(t^2) dt - 2xc1e^(-x^2). Substituting this expression into the original differential equation shows that all terms cancel out, confirming the solution. The discussion emphasizes the importance of understanding the integral's behavior when differentiating. This approach effectively demonstrates the verification process for the given differential equation.
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Homework Statement


Verify that the indicated family of functions is a solution of the given differential equation. Assume an appropriate interval I of definition for each solution.


Homework Equations


dy/dx + 2xy = 1; y = e-x2\int(from 0 to x)et2dt + c1e-x2


The Attempt at a Solution


I have only had one class period in differential so far and we didn't get to go over much material. I imagine that one would need to differentiate y(x) with respect to x and plug into the first equation. However, I'm not quite sure what to do with the integral with respect to t. I tried to integrate it, and got et2/(2t), but evaluating that at 0 would cause an implosion. If I differentiate with respect to x, I don't think I can just treat it as a constant because it's evaluated from 0 to x. Could I please get a nudge in the right direction?
 
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I'm not quite sure what to do with the integral with respect to t.

This is just simple application of Fundamental Theorem of Calculus.

If F(x) = \int_a^x f(t) dt then F'(x) = f(x), given of course that f(x) is continuous on [a, x].
 
So then dy/dx would be:

dy/dx = e-x2 * ex2 - 2xe-x2\int(from 0 to x)et2dt - 2xc1e-x2

And then plugging it into the differential equation, it all cancels out. 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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