If xy + 4ey = 4e, find the value of y” at the point where x = 0.
cannot figure out why I keep getting it wrong.
please show steps if possible
2 Answers

xy + 4ey = 4e
y(x + 4e) = 4e
y = 4e / (x + 4e)
y’ = 4e / ((x + 4e)^2)
y” = 8e(x + 4e) / ((x + 4e)^4)
So when x = 0, y” = (32e^2)/((4e)^4) = (32e^2)/(16e^4) = 2/(e^2).

Answer is 1/(16e^2)
If you have the xy+2e^y=2e variant, then it’s 1/(4e^2). If you have the xy+3e^y=3e variant, then it’s 1/(9e^2), and so on and so forth.
Source(s): I got it wrong on WebAssign, so they showed me the correct answer. I don’t actually know the correct method to solve this. but I thought I would help out all those who don’t have access to Chegg.