TT2-2019 Past Test, Morning Sitting

[YuyingC]

For the morning sitting question in 2019 TT2, why is C2' = e^t/(e^t+1)?

[Jing_Wang]

I encountered the exact same problem and I think (C2)' should equal -e^t/(e^t+1).
Consequently, the constant c2 I find for part (b) is ln2 instead of -ln2.
Also, if it is intended in the question that g = 12/(e^t+1), most things in the solution are to be multiplied by a factor of 6.

[YuyingC]

Yes, I have got the same answer as you. Doubt that the solution is incorrect.