Hi, I have an equation and I want to plot it for a set of inequalities, is this possible or will i need to insert values for the constant?

So if i have the equation;

y=(X_0-aX)/a+(X_0-bX)/b, can I plot y given that: X_0>bX and <aX

Hi, I want to make a plot for different scenarios or limits, but I am not sure if this is possible, so if i have the equation 

X:=A*exp(-a*t)+B*exp(-b*t);

where a and b are pre-defined constants i.e. 1 and 2. I want to plot this for when A>>B, A=B and A<<B, is this possible in maple? 

Hi I am simply trying to rearange equation X, the steoes I want to do are differentiate X w.r.t t then insert equation Y into the new differentiated form but I am stuck, I am not really sure what to try I have used algsubs but it comes up with an error.

here is my code: 

 

X := diff(x(t), t)+(k1+k2+k3)*x(t)-(k4-k1)*y(t)-k1 = 0;
print(`output redirected...`); # input placeholder
/ d \
|--- x(t)| + (k1 + k2 + k3) x(t) - (k4 - k1) y(t) - k1 = 0
\ dt /
Y := diff(y(t), t)+(k4+k5+k6)*y(t)-(k3-k6)*x(t)-k6 = 0;
print(`output redirected...`); # input placeholder
/ d \
|--- y(t)| + (k4 + k5 + k6) y(t) - (k3 - k6) x(t) - k6 = 0
\ dt /
A := diff(X, t);
print(`output redirected...`); # input placeholder
/ d / d \\ / d \
|--- |--- x(t)|| + (k1 + k2 + k3) |--- x(t)|
\ dt \ dt // \ dt /

/ d \
- (k4 - k1) |--- y(t)| = 0
\ dt /
algsubs(Y, A);
%;
Error, (in algsubs) cannot compute degree of pattern in y(t)

 

In a trivial example of where x goes from 0 to 1 of d n(x)/dx =a, where n(0)=1, n(1)=2, so that the integral is solved easily, how can i do this in maple however I can only solve an eqation with the initial condition, if i try anything else then i get errors such as, 

fx := diff(n(x), x)-a

A := rhs(dsolve({fx, x = 0 .. 1, n(0) = 1, n(1) = 2}, n(x)));

Error, (in dsolve) invalid terms in sum: 0 .. 1