You forgot to put a colon. Should be  a:=k-m*L

plot3d([1+2*x-3*y, 2-3*x+5*y], x=-2..2, y=-2..2, axes=normal);

restart;

convert(1/(x^2+2*x+2), parfrac, x, complex);

convert(%, rational);

1.

x:=t->a*exp(mu*t)*cos(t);

y:=t->a*exp(mu*t)*sin(t);

z:=t->b*exp(mu*t);

simplify(a^2*z(t)^2=b^2*(x(t)^2+y(t)^2));

2. For plotting use  plots[spacecurve]  command.

3. For finding the length use the known formula for calculating the length of parametrical curve.

restart;

D[1](u)(1,t)=0;

eval(diff(u(x,t),x), x=1)=0;

Example:

u:=(x,t)->x^2+3*x*t+t^3;

D[1](u)(1,t);

eval(diff(u(x,t),x), x=1);

PP->Insert->Video->Video from file->All Files->Insert

eq1 := x1*a+x2*a+x3*a+x4*a+z = 0:

eq2 := x1+x2+x3+x4 = m:

soln := solve([eq1, eq2], {x1, x2, x3, x4, z});

%[-1];

From the plot, using the mouse, find the approximate values ​​of the roots, and then use Student[NumericalAnalysis][Newton] :

f := 4*x*cos(3*x)+(x-2)^2-2:

plot(f, x = -5 .. 10);

map2(Student[NumericalAnalysis][Newton], f, map(t->x = t, [0.5, 1.6, 2.5, 3.6, 4.8, 5.6, 7.1, 7.4]));

Easier to find all the roots, if you use  RootFinding[Analytic]  command :

sort([RootFinding[Analytic](f, x, re = 0 .. 10, im = -0.1 .. 0.1)]); 

restart;

f:=(x,y)->2+x^2 +1/4*(y^2);

Px, Py:=1, 2;

DPx, DPy:=D[1](f)(Px,Py), D[2](f)(Px,Py);  # Partial derivatives

maximize(DPx*cos(alpha)+DPy*sin(alpha), location);  # Maximum of directional derivative

A:=plot3d(f(x,y), x=-1..3, y=0..4, axes=normal):

B:=plots[arrow]([Px,Py,0],[DPx,DPy,0], color=red):

plots[display](A,B, orientation=[-15,65]);

The length of the gradient vector (the red arrow) is equal to the maximum of the directional derivative, that is  sqrt(5) . The arrow shows the direction of the steepest increase of the function  f(x,y) .

See help page in Maple  Statistics/Regression

Another way is to use  piecewise  command from the outset. This method without a mouse, I think the most comfortable.

piecewise(x<0, x-1, x=0, 0, x>0, x+1);

plot(%, t=0..1,  discont, axes=box);   # zero, except in t=1

Var := indets(EQ):

A, V := LinearAlgebra[GenerateMatrix](EQ, Var);

evalf(LinearAlgebra[LinearSolve](A, V));

B:=cos(x)^2*sqrt(1-1/4*(3*sin(x)^2*cos(y)^2+cos(x)^2));

evalf(Int(B, [x=0..7*Pi/18, y=0..2*Pi]));

 List of errors:

1) Coding of  Pi .

2) Signs of multiplication.

3) Value of the function to the power  n  should be  f(x)^n  rather than  f^n (x) .

4) For double integrals ranges should be in brackets  [x=x1..x2, y=y1..y2] 

GAMMA  is the specific function in Maple, gamma is Euler's constant. See help for details.

evalf(gamma);

GAMMA(5);

               0.5772156649

                       24