I got stuck: What is t if t + 40 = 10e^(t/60)?

ryan_kidz

Junior Member
Joined
Sep 11, 2005
Messages
89
I was doing a diff. equation problem, and I got stuck.

It's kinda a basic math question, but I can't solve it!! :oops:
what is "t" if--> t + 40 = 10e^(t/60)?

can anyone plz try to find it? :?: :?:

Thank you very much
 
Substitution of \(\displaystyle u = \frac{t}{60}\\) gives:

\(\displaystyle 6u - e^u + 4 = 0\)

Then I'd plot the curve y = 6u - e^u + 4 and see where it touches the x-axis, then multiply the result by 60 to find an approximate value for t. Or you could use other numerical methods. Just from looking at it, I'd hazard a guess at u being negative, hence t being a smaller negative number.
 
'u' is also a positive number around 3 - estimated through graphing.
 
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