I have a few suggestions for reducing the time you experience debugging a problem.

1) Normally, in each execution group, write out a single expression with the ";" character at the end to make sure it gets printed.

2) Read the error statement carefully. I agree, Maple error statements can often be confusing, but this one says it pretty clearly - the input is not of the correct format.

For dsolve, it expects a set or list of equations.  {}  means a set. [ ] means a list.

3) Since you have palettes, I recommend that you take advantage of them. However, I will not so that I repeat as much as you have written,

Write out a sequence of equations, i.e., each equation separately,

Writing out a sequence of condition equations

4) It is best to create a variable that is the output from Maple. Then, it is easier to reference your answers.  

For your problem, notice that the sequence of equations are now all inside the set { } inside the call to dsolve.

Note - your answers are not written out because they are long.

5) Since you don't know the order of the output, use eval to reference the results.  The procedure allows you to evaluate for the function of interest from the solutions.

6) Unless you use Maple every day, I suggest using a more intuitively named function to make a function from an expression, MakeFunction.

Hopefully some of the suggestions do help you solve Maple problems more efficiently.

The problem with the document. is that when you create a variable, sometimes you use atomic variables, which are a variable that possesses a subscript, and sometimes you use an indexed variable, such as the nth element of a vector.

It is very easy to tell the difference between the two.

To create an atomic variable with a subscript of 110, either write 'name__110', which generates this output:

or click on this icon in the Expression Palette:

(Now fill in the 'a' and the 'n'.)

To create an indexed variable, either write 'name[110]' which generates this effect:

or click on this icon in the Expression Palette:

By looking at the subscript, you can immediately tell that  is not the same as . The atomic variable possesses an italicized subscript, while the indexed does not.

Since you are not creating a vector Q or a vector β, my recommendation:

a) Don't bother with subscripts. Hence, if you need  , call the variable .
b) Or, if you are going to use subscripts, only use atomic variables: . If you want to identify which are atomic variables and which are not, from the menu bar, select "View  Atomic Variables".

I also recommend switching from using Document mode to using Worksheet mode. When you are experienced with Maple, a Maple document is fantastic. Until then, it tends to lead to more problems.

Are you sure you read the question properly?

2a) Plot the function in 3d:

2b) Limit:

Basic SIR model

Initial condition equations where 1 = 100% of the population.  

Numerically solve with parameters to be modified later.

Extract solutions

Simple example where

Assign the parameters some values and then plot.

Explore the results

1) Create a procedure that substitutes the values sent to it via the Explore procedure into the parameters and then plots.
2) Create an Explore of the Plot procedure.

Slide the sliders to vary the constants.

Since I don't know what this looks like, let's make a collection of space curve.

Copy your text data:

Match with t with the same number of point.

Create a function (using the older version of the MakeFunction procedure) from the data:

And from each point, make a spaaaaace curve.

Next, a generic plot of a collection of space curves

Low-budget version of 3D surface data.

Creating a sequence of points without the option numpoints in the sequence function.

From it, we make "Let's go surfing now; everybody is learning how" data.

And plot

Note bug in 3D plot. Need to report.

Write out  as B and each component of the matrix.

Solve for each component.

Assign each component the value in answer and then write out A