Sorry for the confusion: for dvx/dt=-k/m*x-b/m*vx; at evolution page

The left hand side means dx/dt , the variable at the left hand side means x.

And the variables at right hand side means: x,vx, k,b,m

What I means was that: you can not write the above equation as

dvx/dt=ax; //at [b]evolution[/b] page

and define ax=-k/m*x-b/m*vx; //at [b]fixed relation[/b] page

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oic.... i understand this. use dvx/dt=-k/m*x-b/m*vx; at evolution page.

give Z-D time to understand this.

cheers!