Problem solving a separable differential equation for u

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To solve the separable differential equation du/dt = e^(5u + 2t) with the initial condition u(0) = 13, the user initially attempted to take the natural logarithm of both sides but became stuck. A suggestion was made to use the laws of exponents to split e^(5u + 2t) for easier manipulation. The user expressed frustration, indicating that they were struggling with the problem after a long night. The discussion highlights the challenges of solving separable differential equations and the importance of correctly applying mathematical principles. Continued guidance on the correct approach is needed for a successful solution.
mesa
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Homework Statement


Solve the separable differential equation for u

du/dt=e^(5u+2t)

Use the following initial condition: u(0)=13

The Attempt at a Solution



Honestly I didn't get very far on this one. I took the natural log of both sides,

ln du/dt = 5u+2t

And now I am stuck. Should I divide both sides first by our e^(5u+2t) instead of taking the ln?
 
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mesa said:

Homework Statement


Solve the separable differential equation for u

du/dt=e^(5u+2t)

Use the following initial condition: u(0)=13

The Attempt at a Solution



Honestly I didn't get very far on this one. I took the natural log of both sides,

ln du/dt = 5u+2t

And now I am stuck. Should I divide both sides first by our e^(5u+2t) instead of taking the ln?

Hint: Use the laws of exponents to split e5u + 2t.
 
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Mark44 said:
Hint: Use the laws of exponents to split e5u + 2t.

Damn it...

Thank you, its been a long night.
 
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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