I've got a function y(x) that is initially defined as x^3+y^3=1 and need to plot it, and find y',y''.

At present, I've used implicitplot(x^3+y^3=1,x=0..5,y=0..5) to plot it, but that doesnt seem to work. Also, to find y'

I've used the statement

implicitdiff(g(x,y),y(x),x) where g:=(x,y)->x^3+y^3=1 but this gives me an error that my input is invalid; y(x) is expected to be of the form {(name, set(name), set(function(name))}.

I don't quite understand..

I would like to know how to verify
y=x e5x cos(2x)
is a solution to the differential equation
y(4) -20 y”’+158 y”-580y’+841y=0

I need to plot the maximum of x^2 and sqrt(|x|) together on one graph. I've currently defined a procedure f that uses an if-else construct for the given function. However, when I use plot(f,-3..3); I get the following error:

"Warning, unable to evaluate the function to numeric values in the region; see the plotting command's help page to ensure the calling sequence is correct"

How do I resolve this error?

Hello people in Mapleprimes,

I wish you to teach me about this.

From a matrix, I want to make a string.

pt3 := Matrix(4, 2, [1, 3, 4, 5, 6, 8, 5, 10]);

string1 := cat(

  "(", convert(pt3[1, 1], string), ",", convert(pt3[1, 2], string), ",", ")",

  "==",

  "(", convert(pt3[2, 1], string), ",", convert(pt3[2, 2], string), ",", ")",

  "==",

  "(", convert(pt3[3, 1], string), ",", convert(pt3[3, 2], string), ",", ")",

  "==",

  "(", convert(pt3[4, 1], string), ",", convert(pt3[4, 2], string), ")"

)

The above code makes 

string1 := "(1,3,)==(4,5,)==(6,8,)==(5,10)"

What I want to know is how to write a code of programming without writing each row of the above code.

Actually, though I wrote 4 row matrix above, the number of rows of matrix I want to deal with might be more than 100.

Best wishes.

taro

I am new to Maple. I am working though the manual and in chapter two I tried to get the derivative of ln(x^2+1). I am getting something completely different that the actual derivative. I tried a simple derivatie (the derivative of 2x and get 0). I do not know what I am doing wrong. Any help will be appreciated.

How can I link the axes in two or more separate plots so that when I zoom in one, the others are also zoomed. Also when I want to link the 'x' or the 'y' axis only.

Thank you

Dear mapleprimes users,

I have a problem with the LeastSquaresPlot(A0,[p, sec ]) function, for the vector A0, then it gives the error:

Error, (in Student:-LinearAlgebra:-LeastSquaresplot) all points must evaluate to numeric values.

I tried to convert the vector A0 to numeric values, but I didn`t succeed yet. I take A0 = vector(1..10,2) as an example, but still I get nothing.

Thanks for the help!

Yours

I've got the following equations :

x^3-4x=y, y^3-3y=x that I want to plot together over an appropriate range for x and y

I've tried plots[multiple]([eq1,x=-2..2,y=-2..2],[eq2,x=-2..2,y=-2..2]) 

but that doesn't seem to work. How can I rectify this error?

Following is the set of commands I performed.

> points := plots[implicitplot](t+sin(8*x^3*t)-x^3 = 0, t = -0.50e-1 .. 0.5e-1, x = -10/9 .. 10/9);
print(??); # input placeholder
> ptslist := convert([1, 1], points, listlist);

In an output I need the data at the specified values of t. It will be great favor, if someone can help me out.

Thanks

This is a very simple suggestion that weights heavily on my enjoyment of Maple.

I'm not sure if it is only me and my students but it is really tricky to resize a code edit region. Trying to get a hold of the contour in an exercise in patience! Can anyone fix this?

Thanks!

Stéphane

I'm trying to verify whether the result obtained from a recursive Legendre function that I defined is the same as that obtained from the function available in Maple.

The arguments for LegendreP() mentioned seem to be v,x where v is the algebraic expression's degree and x is the expression. I tried calling the function as LegendreP(6,x) since I am to obtain the value at n=6 but this statement is not giving me an output in return that I can use to compare.

Would I have to plot both functions in order to be able to compare them?

I've got a pair of equations :

x^3-4x=y and y^3-4y=x

 which I've defined as eqns:={,}

and 9 solutions as solns1:={,,..}

and being stored as s1,s2,..s9

when I run a command such as testeq(subs(s1,eqns[1])=subs(s1,eqns[2])

I get an error of passing invalid arguments into testeq. What I essentially need to show is that on substituting for x,y from each s1,..s9; both equations get the same result. What am I doing incorrectly?

I've also noticed that just subs(s1,eqns[1]) returns an equality; I don't quite understand why

Dear mapleprimes users,

I have a problem with this function:

B is the length of my array

A := Array(1..B,0);

for i from 1 to B do
p = nextprime(i)

a = primroot(p)

A[i] := A[i] + convert((Usage(mlog(b,a,p,method=indcalc), output=[cputime,output],quiet)[1],decimal,15))
end do;

A;

My idea is to create an array A with all the CPUtimes from the 1st prime til the Bth prime, and then plot it.

But my problem is that I get an error; Illegal use of an object as a name.

I don`t know what to do could you help me?

Thanks!

I'm given the following two equations:

x^3-4x=y, y^3-4y=x

to solve the system, I've just used

eqns:={x^3-4x=y,y^3-4y=x};

vars:={x,y};

solns:=solve(eqns,vars);

and have obtained only four solutions when I should instead get 9. Is there a mistake in my approach?

Here's my problem,

I'm this line of code

result:=solve({x+y=1,x+2y=4},{x,y})
and the value of result is
{x=-2,y=3} and the value of result[1] is x=-2.

I would like the value of result to be {-2,3} for I need to use those output later. Is there any way to put those output in a list?