# Homework Help: Manipulating equation

1. Feb 1, 2008

### romd

Hi, I need help manipulating the equation

x(t)=e^(-t/tau) sin(omega*t)

into a straight line graph (y=mx+c) of position (x) against time (t)

edit: this might have been better off in the homework/coursework section, sorry

2. Feb 1, 2008

### Mentz114

Do you mean x = m.t + c ?
Are you allowed to make co-ordinate transformations ? The equation describes a damped oscillator so there doesn't seem to be any other way.

3. Feb 1, 2008

### romd

The question is "make a straight line out of what"? The graph of the function you give, $$x(t)=e^{-t/\tau} sin(\omega t)$$, in the "tx-plane" is certainly not a straight line and there is no y. The graph of that would be a "wave" getting smaller and smaller as t increases. Sometimes you can make a function into a linear graph by plotting the logarithms of the values rather than the values themselves, but that won't work with that "sin" there.
$y= me^{-t/\tau} sin(\omega t)+ b$. The values given by those functions will give the position, at time t, of an object moving along the line y= mx+ b.