>restart: with(Student[Calculus1]):
>Roots(cos(x),0..3*Pi);

[1/2*Pi, 3/2*Pi, 5/2*Pi]
 

For Maple 12 you can take a look at this thread.  I do not have v13 loaded at home yet so I can't see if this changed.

Here is an example, modify to fit your needs:

>restart: with(plots):

>p1:=plot(x^2,x):

>p2:=plot(x-1,x):

>display(array([p1,p2])); # rows of plots

>display(array(1..2, 1..1, [[p1],[p2]])); # lines of plots
 

What version of Maple are you using?  I tried this with version 9.51 (Classic and Standard) and with version 12 (Classic and Standard).  I do not see what you are seeing.  The options to make the changes in Classic are in a different location on the menu compared to Standard.  In Classic, you have to select File-Preferences-Numerics.  In Standard, it is as I mentioned in my previous post.  One more thing.  Once you make the change, you have to re-execute your worksheet in order for the changes to take effect.  There is also the option to Apply to Session or Apply Globally.   I selected Apply to Session.

The Standard Interface supports this.  Go to Tools, Options, Precision and check the box "Round screen display to..." and pick a number.  The default is 10. 

evalf(10.5,10);

yields

10.5000000000

Regards,
Georgios Kokovidis

In 3D plots, by default, the axis is not shown, using the plot3d command.  I have not tried it with other 3D plot styles.  In order to show the origin @ 0,0,0 you can add the "normal" axes option to your plot command.  See both versions below for an example.

plot3d(binomial, 0..5, 0..5, grid=[10,10];

plot3d(binomial, 0..5, 0..5, grid=[10,10],axes=normal);

Another way is to use the first version above, right click on the plot, go to Axes, and select normal.

Take a look at the help files for the assign command.

?assign

The explanation has to do with the note after the minimum comment.

Note: plot employs an adaptive plotting scheme which automatically does more work where the function values do not lie close to a straight line. Hence, plot often generates more than the minimum number of points.

So, for you particular example, 50 works, but that does not mean that Maple chose a value smaller than 50.  For example, using numpoints=60 will give a plot that is not as nice as using numpoints=50.  Because of the adaptive plotting routine, it so happens that a number was chosen that was not ideal for your particular function.

Hope that helps.
 

Look at the help file for plot/options.  Then take a look at numpoints=n.  Increasing this beyond the default will take care of the jagged edges in your plot.

plot(cos(2*x^2),x,numpoints=1000);

shold give a pretty smooth plot.  If it is not to your liking, you can increase the number.

Maple does not understand e^.  The exponential function is exp().  Look at the help file for clarification.

?exp

Then rewrite your equations using exp instead of e^ and see what happens.

Look for the Green Arrow icon right above the place where you enter text.  Click on it and browse to the directory where you file is.  Select it and then click Upload.

Look at the help pages for the spacecurve command.  You have to load the plots package in order to use it.

?spacecurve

Here is one way to plot the intersection.

>restart: with(plots):

>f:= x -> 3*x^2-22*x+7;

>g:= x -> -5/9*x^2+58/9*x-161/9;

>plot1:= plot(f(x), x = 0..8,thickness=2):

>plot2:= plot(g(x), x = 0..8,color = green,thickness=2):

>plot3:=seq( plot([1 + i * (6/100) , t, t = f(1 + i*(6/100))..g(1 + i * (6/100))], thickness=5, color=blue), i = 1..99):

>display(plot1,plot2,plot3);
 

For the area, your calculation for f(x)=3*x^2-22*x+7 gives the value for the x-axis intersection.  To find the area of intersection of the two parabolas, use int(f(x)-g(x),x =a..b) where a and b are the two points on the x-axis where these two functions cross each other.  Set one equal to the other and use the solve command to get the values.

An example below that you can modify with your own equation.  At each step, you should read the associated help file for the command.

1:  Start with a plot.  I will use x^2-10 as my equation.

>plot(x^2-10,x);

2:  Solve the equation for x so that you can determine the limits of integration.  i.e. where does this parabola cross the x axis.

>solve(x^2-10,x);

3:  Using the output of the solve command above, use those values as your limits of integration for the area of the parabola.

>int(x^2-10,x=-10^(1/2)..10^(1/2));

Use your equation instead of mine, and see what happens.  One more thing; I would use the multiplication sign (*) in between 3x^2, like this:  3*x^2 as well as in other areas where you are multiplying a constant with a variable.

Here is one way

>restart:

>ans:=solve(3*x^2-9*x+11,x);

ans := 3/2+1/6*I*51^(1/2), 3/2-1/6*I*51^(1/2)

>x:=ans[2];

x := 3/2-1/6*I*51^(1/2)

>x;

3/2-1/6*I*51^(1/2)