# Solve : 9 cosh9y dy = 4 sinh 4x dx

1. Apr 1, 2005

### Naeem

I did this:

9 Integral cosh9ydy = 4 Integral sinh4xdx

9/9 sinh9y + C = -cosh4x
C = - cosh4x -sinh9y

Is this right , or wrong, or is there more to it.

2. Apr 1, 2005

### Zurtex

This is wrong, you will find the sign does not change when integrating sinh or cosh.

Also if you wanted an explicit equation, there are ways of simplifying it (actually you'd probabily need some initial conditions).

Last edited: Apr 1, 2005
3. Apr 2, 2005

### dextercioby

$$\int \sinh x \ dx =\cosh x +C$$ !!

Daniel.

4. Apr 2, 2005

### Jameson

$$9\int\cosh{9y}dy = \frac{9\sinh{9y}}{9} + C = {\sinh{9y}} + C$$

$$4\int\sinh{4x}dx = \frac{4\cosh{4x}}{4} + C = {\cosh{4x} + C$$

Last edited: Apr 2, 2005