## 749 Reputation

11 years, 87 days

## use op...

i changed your x to x[k] so that u can know your x in every loop. good luck

 > restart:
 >
 > a := Matrix([1, 2, 3, 4, 5]);
 >
 > for k  to 5 do
 >
 > x[k] := rhs((op(op(3,(DirectSearch:-SolveEquations(a(1, k)*x[k]+2 = 0))))))
 >
 > end do;
 >
 (1)
 >

## it works on maple 18...

 > restart:
 > restart;  local `+`;  `+`:=proc(a,b) :-`+`(a^`~2`,b^`~2`) end proc;
 (1)
 > `+`(a,b);
 (2)
 >

## first solve with respect to your praamet...

 > restart:
 > q := a*mu^4+b*mu^3+d*mu^2+e*mu+f = 0;PARAM := [a = -54/c^2-1269*A[1]/(8*c^2), b = 108/c^2+5013*A[1]/(8*c^2), d = 27-693/(2*c^2)+117*A[1]-7113*A[1]/(4*c^2), e = -27+585/(2*c^2)-111*A[1]+20439*A[1]/(16*c^2), f = 1-3*A[1]-18/c^2-8*A[1]/c^2];
 > ans:=solve(eval(q,PARAM),mu);solve(eval(q,PARAM),mu,parametric=full);
 (1)
 > ans1:=series(ans, A[1]=0,  2);ans2:=series(ans1, c=infinity,  3);
 (2)
 >
 >
 >

## u can also turn off warning message...

u can use
interface(warnlevel=0);

to suppress all warning messages,but here as carl says your warning's was due to assigning local varibales,good luck

## you have assigned i to be an input,and a...

when u assign i to be an input thus it is a known number, but u have assigned also i in sequence which has the values from 1 to ,,, ! thus it returns an error.
after removing i from input ,there are some other errors,which u should check your code line by line ,good luck

## implicitplot...

 > restart:x::real;
 > eq:=-32.46753247/(Pi*x^2)+1.053598444*10^8*Pi^2*y/x^2-5.342210338*10^14*Pi^2*y*(2.574000000*10^8*Pi^2-.7700000000*x^2)/((-3.904240733*10^6*x^2+1.305131902*10^15*Pi^2-159.8797200*Pi^2*x^2+2.672275320*10^10*Pi^4+2.391363333*10^(-7)*x^4)*x^2)+1.504285714*10^9*Pi^4*y^3/x^2=y ;
 (1)
 > plots:-implicitplot(eq,x=0..10,y=0..x);
 >

## use numerical definite integration...

 > restart:a:=8:b:=10:
 (1)
 >

## u can do it in many ways,...

A.as maple help page :

To export a plot:
1. Select the plot you want to export.
2. From the Plot menu, select Export.
Alternatively, right-click (Control-click, for Macintosh) the plot you want to export. The context menu appears. Select Export.
3. Select a format.
4. Specify the location and the name of the exported file.
Click Save.

B. you can easily right click on your plot,select copy and open a word file and select paste . now your plot has been copied.

C. u can export your plot data into excel and thus save your plot as a picture file,

D. if u have windows 7 , go to start-all programs-Accessories-Snipping tool, double click on it, and it will provied you a frame to choose and give you back the pictrue u want from every where.

E. you can also take a picture from your screen by PrtSc and save it into a document and then snip your plot from it .

good luck!

## use op...

 > restart:
 > with(plottools):
 > with(plots):
 > display(cylinder([1, 1, 1], 1, 3), orientation = [45, 70], scaling = constrained, grid = [2, 2, 2]);
 >
 > op(op(1,%));
 (1)
 >

## use doslve...

 > restart:
 > ans:=dsolve(diff(y(x),x)=(y(x)^3+y(x)*x^2)/x^3);isolate(op(2,{ans}),ln(x));
 (1)
 > # thus,the forth choice is correct !
 > ans2:=dsolve(diff(y(x),x)=(y(x)^2+y(x)*x-x^2)/(y(x)*x));
 (2)
 >
 > isolate((ans2),_C1);
 (3)
 > #thus the best answer is the first choice # note that ln(a)-ln(b)=ln(a/b)# and x^2=abs(x)*abs(x)#
 >

## one way,...

u can see the curve's function's and curve fitting equations are almost the same,good luck !

 (1)

 (2)

 (3)

 (4)

 (5)

## your problem is at option gridline...

 > restart:
 > Student[Calculus1]:-Tangent(tan(3*x)-5*exp(-x^3),x=0,output=plot,axis = [gridlines = [18, color = blue]],caption="Tangent plot");
 >

## do u want to plot in every step of you l...

for your last step u can do :

 > restart:
 > #Parameters
 > L := 20; Q := 20; n := 8; h := 3; EAv := 1;
 > Mat := Matrix(10, 2, storage = sparse);
 > a := 1;
 > #loop L1
 > for L1 from .6 by .1 to 1.5 do
 > L1 := L1;
 > L2 := 2*L1;
 > L3 := 1.6*L2;
 > L4 := (1/2)*L-L1-L2-L3;
 > alfa1 := evalf(arctan(h/L1));
 > alfa2 := evalf(arctan(h/L2));
 > alfa3 := evalf(arctan(h/L3));
 > alfa4 := evalf(arctan(h/L4));
 > F4 := (1/2)*Q*L4;
 > F3 := (1/2)*Q*L3+(1/2)*Q*L4+F4;
 > F2 := (1/2)*Q*L2+(1/2)*Q*L3+F3;
 > F1 := (1/2)*Q*L1+(1/2)*Q*L2+F2;
 > w1 := evalf((1+sin(alfa1)^3)*F1*L1/(EAv*sin(alfa1)^2*cos(alfa1)));
 > w2 := evalf((1+sin(alfa2)^3)*F2*L2/(EAv*sin(alfa2)^2*cos(alfa2)));
 > w3 := evalf((1+sin(alfa3)^3)*F3*L3/(EAv*sin(alfa3)^2*cos(alfa3)));
 > w4 := evalf((1+sin(alfa4)^3)*F4*L4/(EAv*sin(alfa4)^2*cos(alfa4)));
 > kkm := (w1-w2)^2+(w2-w3)^2+(w3-w4)^2; Mat(a, 1) := L1;
 > Mat(a, 2) := kkm;
 > a := a+1;
 > end do:
 >
 (1)
 > plots:-pointplot([seq]([Mat(i,1),Mat(i,2)],i=1..10));
 > plot([seq]([Mat(i,1),Mat(i,2)],i=1..10));
 >

## use fsolve...

 > restart:
 > eq1 := 3*(1+sin(alfa1)^3)(30/tan(alfa1)+60/tan(alfa2)+60/tan(alfa3))/(sin(alfa1)^2*cos(alfa1)*tan(alfa1)) = 3*(1+sin(alfa2)^3)(30/tan(alfa2)+60/tan(alfa3))/(sin(alfa2)^2*cos(alfa2)*tan(alfa2));
 >
 > eq2 := 3*(1+sin(alfa1)^3)(30/tan(alfa1)+60/tan(alfa2)+60/tan(alfa3))/(sin(alfa1)^2*cos(alfa1)*tan(alfa1)) = (90*(1+sin(alfa3)^3))/(sin(alfa3)^2*cos(alfa3)*tan(alfa3));
 >
 > eq3 := 3/tan(alfa1)+3/tan(alfa2)+3/tan(alfa3) = 25/2;
 >
 >
 (1)
 > solutions := fsolve({eq1, eq2, eq3}, {alfa1, alfa2, alfa3}) assuming alfa1 > 0, alfa2 > 0, alfa3 > 0;
 (2)
 >

## u can not have both P(x) and R(P)...

for soliving your pde numerically , you should specify your P(x) and R in terms of known functions of x !
and also you need to have your boundaries !

if we change R(P) by R(x) , we can have :

 > restart:
 > sys:={dy(x)/dx +y^2 =P(x), dP(x)/dx = R(P)};
 (1)
 > dsolve({sys});
 > sys:={dy(x)/dx +y^2 =P(x), dP(x)/dx = R(x)};dsolve({sys});
 (2)
 >

for more detailed answer, u should specify P(x) and R(x), and u can also see ?dsolve