That's the same answer I came up with.

You can set this up by hand, and then use Maple to solve for the unknowns.  Using the formula for mixing solutions of different concentrations, you will get this.

V1+V2=10

V1*C1+V2*C2=Vf*Cf

V1 and V2 are what you are solving for.  You know C1, C2 and Cf (concentration levels).  You also know what Vf is.

Show what you have done so far as setting up the equations with the unknown, and if you need help with the Maple side, we can show you how to use the solve command to get to the answer.

The seq command in Maple 12 supports and increment parameter, so the above can be done as follows:

pts := [seq([x,x*2+3*x^2],x=1..5,0.1)];

plot(pts,style=point);

Doug's method is more general and can be used with previous versions of Maple that do not support the 3rd parameter in the seq command.

Another option might be the Roots function in the Student[Calculus1] package.  Starting with a plot is a good idea.  It will give you a visual of the range you can expect to find roots.

>restart:

>with(Student[Calculus1]):

>Roots( 23*sin(x) + x - 1, x=-20..20,numeric);

[-17.88615524, -16.57784743, -11.96739147, -9.919468724, -5.975069324, -3.331029271, .4167822926e-1, 3.239099228, 6.061312345, 9.818255382, 12.06450120, 16.44417544, 18.01669892]

Take a look at the help files for the commands below.  You can cut and paste the examples in the help files and change the function to match your own.  At the Maple prompl, type the commands below and hit the enter key or open up the help browser in Maple and look for the commands.

?implicitplot

?contourplot

The way you defined your function is incorrect.  Try the following:

f:=x->1-abs(x);

Then this:

a[0]:=int(f,x=-1..1);
a[n]:=int(f*cos(n*x*Pi),x=-1..1);
b[n]:=int(f*sin(n*x*Pi),x=-1..1);
 

Then your plot should work.

For help look at:

?operators/functional

As you mention, this zoom is not very useful.  That is why I prefer the range variables.  This feature would be useful, if it did rescale and recalculate.  Another feature I would like to see in a future version is a bounding box that I can drag over a region of a plot and zoom in on that.

The Standard Gui supports zoom with a mouse while the Classic does not.   For example, using a command from the help pages:

plots:-implicitplot3d(x^3+y^3+z^3+1 = (x+y+z+1)^3, x = -2 .. 2, y = -2 .. 2, z = -2 .. 2, grid = [13, 13, 13]);

Using the Standard Gui, if you right click on the plot, select Manipulator, and then Scale, you will be able to click into the plot (hold the left mouse button down) and slide the arrow up and down.  Up will zoom in while  down will zoom out.  I prefer the Classic Interface with intervals for each of the x,y,z axes.
 

Try a multiplication sign between the x and y in xy^2:

implicitplot3d(z = x*y^2/(x^2+y^4), x = -4 .. 4, y = -4 .. 4, z = -.5 .. .5, grid = [30, 30, 30]);

restart:

n:=1;

diff(1/(1+x^2),x$n);

Change the value of n to get higher order derivatives.

>?assign

> restart:
> eq1:=x+y=2:
> isolate(eq1,y):
> assign(%):
> s=z+y;
 

The code below assumes values for x0.  You can use your own.  If you know the values for e,f,g and h, then you will get and equation that you can plot as your final answer.

restart:

P:= x -> a*x^3+b*x^2+c*x+d;

locmax_conditions := {P(-1)=e,D(P)(-1)=f};

locmin_conditions := {P(4)=g, D(P)(4)=h};

solve(locmax_conditions union locmin_conditions);

subs(%,P(x));

How are you computing the derivatives?  Are you using the diff command, or some other method.  For more help and details, take a look at the help files for diff.

>?diff

>diff(cot(x/2),x);

-1/2-1/2*cot(1/2*x)^2

>diff(cot(x),x);

-1-cot(x)^2

>diff((z-1)/(z+1),z);

1/(z+1)-(z-1)/(z+1)^2

 Start here.

 This link might be of interest as well.

The following commands might be useful for your algorithm.  Look at the help pages for syntax and how to call them. 

?VectorCalculus[Hessian]

?LinearAlgebra[IsDefinite]

Section 5.2.2. of the text:  Interactive Operations Research with Maple: Methods and Models deals with this subject, and has pointers to other references with proofs.  The website of the text with code is here.  The examples used in the text are based on the linalg package from Maple V5.1 & 6.  The linalg package has been superseded by the LinearAlgebra and VectorCalculus packages.