Hi

i am working on a simple control project.i should make a transfer function from the below equation (as an example):

 (s^2*m1+I1*(s^2)*(1/r^2))*x(s)+(-(1/2)*s^2*b*m1-s^2*m1*r-I1*(s^2)*(1/r)+m1*g)*theta(s)+(1/2)*theta(0)*s*b*m1+theta(0)*s*m1*r-x(0)*s*m1+(1/2)*(D(theta))(0)*b*m1+(D(theta))(0)*m1*r-(D(x))(0)*m1+I1*s*theta(0)*(1/r)+I1*(D(theta))(0)*(1/r)-I1*s*x(0)*(1/r^2)-I1*(D(x))(0)*(1/r^2) = 0

in order to make the T.F i have to make " x(s)/theta(s) " on the lhs and put the rest on the rhs. i have no idea how to do so.(the underlined part involves no x(s) and theta(s). obviously a theta(s) will appear on the rhs in the one of the denominators which doesn't matter.)

please help me with this problem.since i don't know what the commands are called in english, i failed in searching for it.

thanks.

hi. i am tottaly new to the maple and i have a problem.

consider function f with variables x & y which are not independent. x & y are functions of t and the relation is unknown.

for example i wanna to the below job:

define f as f=x^2+y^2

differentiate it with respect to t : diff(f,t) which should give me 2(dx/dt)x+2(dy/dt)y

i've googled it alot and i couldn't find anything usefull.

(the problem is how to set x as a function of t with unknown relation and use it in another function and then differentiate it with respect to t)

thanks alot :)