Question

Find dy/dx and d^2y/dx^2. For which values of t is the curve concave upward?

x=t-e^t
y=t+e^(-t)

Answer 1

\[x=t-e^t\]
\[y=t+e^{-t}\]

Answer 2

I have this answer

Answer 3

Help please @Ket-kat

Answer 4

x + y = e
−t
+ e
t
= 2cosh(t). Therefore t = arccosh((x + y)/2)

Answer 5

uh @Ket-kat , what did you do?

Answer 6

http://www.aerostudents.com/files/calculus/solutions/calculus_solutions_10_2.pdf

I think this will make more sense for you; they are similar questions so you can see how to work them out. If you don't get it, message me :)