# Hyperbolic functions

1. Sep 29, 2009

### nameVoid

y=km(ln(cosh(gt/km)^(1/2)))
constants k and m
dy/dx=gtanh((gt/km)^(1/2))/(2(gt/km)^(1/2))...?

2. Sep 29, 2009

### Staff: Mentor

Don't think so, but I'm not sure how the problem is actually stated.

Is it
a)$$y = km~ln(\sqrt{cosh(gt/(km))}~)$$

or
b)$$y = km~ln(cosh(\sqrt{gt/(km)}~))$$
?
As you wrote the problem, it would be a, but your derivative (which should be dy/dt) suggests it is b.

3. Sep 29, 2009

### nameVoid

b sorry my mistake im working on the second derivative now it seems a bit to messy but I dont see an error in y'