#### Hyperionza

##### New Member

I am a masters in computer science student so my knowledge of electronics is pretty much that of a hobbyist. Unfortunately my dissertation touches into the realm of analogue computers, and, to be frank Im a little lost.

My problem is that, in an example Im using, Im required to differentiate two dependent variables, call them

*x*and

*y*. However, it is my understanding, that in an analogue computer, you may only differentiate one dependent variable per op-amp and your independent variable is time.

Thus I know I can compute dx/dt and dy/dt. But, how can I relate them to give me dy/dx?

Is it possible to, in an analogue computer do the following to achieve the result I want. I remember seeing something like it somewhere but Ive no idea where!

1.1) Calculate dx/dt

1.2) Calculate dy/dt

2) Invert dx/dt (ie: 1 ÷ dx/dt)

3.1) ln(1 ÷ dx/dt)

3.2) ln(dy/dt)

4) add 3.1 to 3.2

5) antilog the result of 4

If Im completely wrong, would someone mind please steering me on the right course? Google hasnt been very helpful today...

Thanks in advance!