## "expand" command does not act as it should...

Hello!

I am working with the Maple 18.02 version. I just want want to perform a basic polynomial expansion using the command "expand" and it does not respond as it should according to what Maple Programming Help says it would. For example:

Maple Programming Help says:

I get:

.

Also, one sees that this isn't even true, as x(x+2) + 1 = x^2 +2x +1, which is not equal to x^2 + 3x +2.

Moreover, maple tells me it is equal..:

What is going on here? I woul like to get the full expanded form (without factors). Also, this is obviously not true, or maybe Maple means something else by x(x+2) +1...

Thank you!

## Apply igcd to a list...

I have a list of univariate polynomials

P:=[x^2-7*x+10, x^2, x^2+2*x+1]

How do I get the gcd of all of these?

It doesn't like it when I do the following:

igcd(P)

Thanks

## Question: How to i convert a complicated equations...

Hi everyone, i am using Maple 18 and i have a problem in converting a equation to a nice polynomial form (a cubic equation with a form of A*x^3+B*x^2+C*x+D), can anyone please help me on the command? Thanks in advance.

My equation is "  d := s*x*(E*K*q-K*r+K*sigma[1]+r*x)*(1-x*(E*K*q-K*r+K*sigma[1]+r*x)/(K*sigma[2]*L))/(K*sigma[2])+sigma[1]*x-x*(E*K*q-K*r+K*sigma[1]+r*x)/K  " or for simplicity is

Can someone please teach me on the command? Really appreciate the help!

## Get homogenous expressions from symmetric polynomi...

How to get homogenous expressions from symmetric polynomial.

Example. Let P = (a^2 + 2)(b^2 + 2)(c^2 + 2), we have deg(P) = 6. I want to get polynomials of degree n on A[n] with n = 0, 1, ..., 6. Specific

P = a^2b^2c^2 + 2(a^2b^2 + b^2c^2 + c^2a^2) + 4(a^2 + b^2 + c^2) + 8.

And

A[0] = 8

A[1] = 0

A[2] = 4(a^2 + b^2 + c^2)

A[3] = 0

A[4] = 2(a^2b^2 + b^2c^2 + c^2a^2)

A[5] = 0

A[6] = a^2b^2c^2

Thank you very much.

## Factoring polynomials in real radicals...

Hi!

I a have a question about factorizing real polynomials.

Suppose I have a real polynomial p(x) with integer coefficients. If the degree of p(x) is less than or equal to 4, we can factorize it into linear radical factors. On the other hand, if we require the factorization to be real, theoretically we can factorize it into linear and irreducible quadratic factors.

My question is, if the input p(x) is real polynomial with integer coefficients, is there any Maple function that can give me factorization output with real linear and irreducible quadratic factors, with radical coeffs?

For example, I tried q := 20*x^3+10*x^2+4*x+1, it has one real root and 2 complex roots. I want a factorization like q(x) = 20*(x-r1)*(a*x^2 + b*x + c), with r1, a, b, c, all real radicals.

I compared functions: factors(), solve(), sqrfree(), Splits(), and none of them give what I want.

factors(q) gives:
[20, [[x^3+(1/2)*x^2+(1/5)*x+1/20, 1]]]

factors(q, real)  gives:
[20., [[x+.3423840948583691316993036540027816871936619136844427977504078911, 1], [x^2+.1576159051416308683006963459972183128063380863155572022495921089*x+.1460348209828001458360112632660894203743660942160039146818509889, 1]]]

solve(q)   gives:
-(1/30)*(350+105*sqrt(15))^(1/3)+7/(6*(350+105*sqrt(15))^(1/3))-1/6, (1/60)*(350+105*sqrt(15))^(1/3)-7/(12*(350+105*sqrt(15))^(1/3))-1/6+(1/2*I)*sqrt(3)*(-(1/30)*(350+105*sqrt(15))^(1/3)-7/(6*(350+105*sqrt(15))^(1/3))), (1/60)*(350+105*sqrt(15))^(1/3)-7/(12*(350+105*sqrt(15))^(1/3))-1/6-(1/2*I)*sqrt(3)*(-(1/30)*(350+105*sqrt(15))^(1/3)-7/(6*(350+105*sqrt(15))^(1/3)))

[20, [[(1/30)*(350+105*sqrt(5)*sqrt(3))^(1/3)+1/6-7/(6*(350+105*sqrt(5)*sqrt(3))^(1/3))+x, 1], [-(1/60)*(I*sqrt(3)*(350+105*sqrt(5)*sqrt(3))^(2/3)+(35*I)*sqrt(3)+(350+105*sqrt(5)*sqrt(3))^(2/3)-60*x*(350+105*sqrt(5)*sqrt(3))^(1/3)-10*(350+105*sqrt(5)*sqrt(3))^(1/3)-35)/(350+105*sqrt(5)*sqrt(3))^(1/3), 1], [(1/60*I)*sqrt(3)*(350+105*sqrt(5)*sqrt(3))^(1/3)+(7/12*I)*sqrt(3)/(350+105*sqrt(5)*sqrt(3))^(1/3)-(1/60)*(350+105*sqrt(5)*sqrt(3))^(1/3)+1/6+7/(12*(350+105*sqrt(5)*sqrt(3))^(1/3))+x, 1]]]

None of them give me what I want. Is there any build-in function that can help me do that?

Thanks!

William

## Symbolic cut-off of high-order terms...

Hi! I have a variable polynomial expression and I want to cut off all the terms of order 3 and more, for every product of variables.

For example consider the polynomial `P = x + y + a*x^2 + b*x^3 + c*x*y + d*x^2*y + e*x*y^2 + y^2`, I want an operation who returns me `a*x^2 + c*x*y + y^2`

(terms for which the sum of exponents in `x` and `y` exceeds or less two are being deleted)

Is it possible?

## move 1 under sqrt...

Silly, but what command will move the one first under the sqrt here...

a:=sqrt(1+x^2)  # maple moves the x^2 in front
sqrt(x^2+1)

What maple command will move the 1 in front of the x^2 under the square root?

## Multiply each term from a polynom by a coefficient...

Hi there,

I have a big polynomial expression involving powers of x and y, that comes from expanding a function in powers of x and y in polynomial form (I use series(convert(series(a,x=0,10),polynom),y=0,10) ). I want to multiply each of the terms by the factorial of the power of x and y it has. How can I do this?
I tried using Physics[Coefficient](a,x) but I get the error: it cannot compute the degree of the expression.
I tried using a double for with a double coeff to get each of the coefficients and the maybe be able to multiply them but I get the error "unable to compute coeff".

Is it because as expanding the series I have the term +O(y^11) that it cannot compute it?

I managed to substitute the x terms using subs(x^3=3!*x^3,x^5=5!*x^5,a). Obviously this is not very efficient since I need to write the substitution for each term, and since the ploynom is grouped in powers of y, this does not work for y (neither does algusbs).

[Edit 2]:

an example of it would be:

with result

And I want the coefficients for each x and y power to be multiplied by the factorial of those powers.

Thank you!

## Assume products of variables are zero in large set...

I am interested in the behaviour of a system of equations close to the origin- these equations are quite long, and there are a lot of them so i would like to have commands that i can use to assume products of variables are zero.

here are the first two polynomials:

alpha*k[a1]*B[1]^2+(-alpha*k[a1]-alpha*k[a2])*B[2]*B[1]+2*alpha*k[a1]*B[1]*B[11]+alpha*k[a1]*B[12]*B[1]+2*alpha*k[a1]*B[1]*B[211]+alpha*k[a1]*B[221]*B[1]+2*alpha*k[a1]*B[1]*B[2211]+(-alpha*R[b]*k[a1]-k[d1])*B[1]+2*B[11]*k[d1]+B[12]*k[d2]+k[d1]*B[211]+k[d2]*B[221]

(-alpha*k[a1]-alpha*k[a2])*B[2]*B[1]+alpha*k[a2]*B[2]^2+2*alpha*k[a2]*B[2]*B[22]+alpha*B[2]*B[12]*k[a2]+alpha*k[a2]*B[2]*B[211]+2*alpha*k[a2]*B[2]*B[221]+2*alpha*k[a2]*B[2]*B[2211]+(-alpha*R[b]*k[a2]-k[d2])*B[2]+B[12]*k[d1]+2*B[22]*k[d2]+k[d1]*B[211]+k[d2]*B[221]

the varables are the terms with B and a subsript and everything else is a parameter.

My intuition was to use coeffs but I couldn't get anything helpful

## Factorization of multivariable polynomial not work...

Already searched and browsed multiple different threads and still cannot find a solution.

Apologizing the noob nature of this question.

In this code below, Why is the factor command not working?

 (1)

 (2)

 (3)

## How to do simultaneous fitting...

Dear All,

I am a new Maple user and I am still unaware of a lots of fancy features of Maple. I have a problem of simultaneous fitting polynomials. I wish that I could have help from you. Say, we have two polynomials of two variables,

f1(x,y)=a1+a2*x+a3*y+(a4+a5)*x2+(a4-a5)*y2;

f2(x,y)=b1+b2*x+b3*y+(a4-a5)*x2+(a4+a5)*y2.

Note that a4 and a5 are shared by the two polynomials. I would like to fit the two polynomials against their respective data set. Is there anyway I can do it using Maple? Any of your help is highly appreciated!

Best regards,

Toby

## why area2 has rootof?...

updated:

with(CurveFitting);
f := PolynomialInterpolation([[0, x0],[1, x1],[2, x2],[3, x3],[4, x4]], x);
f2 := solve(f=y,x);
area1 := int(f, x=0..1);
with(student):
area2 := trapezoid(f2[1], x = 0..1);
with(CurveFitting);
f := PolynomialInterpolation([[0, x0],[1, x1],[2, x2],[3, x3]], x);
f2 := solve(f=y,x);
area1 := int(f, x=0..1);
with(student):
area2 := trapezoid(f2[1], x = 0..1);

i use 5 points trapezoid got RootOf  in result,

only 4 points is acceptable

when i try 5 points, there is no problem, but when more points such as

30 points, got RootOf for c sharp code

moreover, i got a problem when i copy the area1 result into

visual studio c# code, it has error Integral Constant is too large

with(CurveFitting);
f := PolynomialInterpolation([[0, x0],[1, x1],[2, x2],[3, x3],[4, x4],[5, x5],[6, x6],[7, x7],[8, x8],[9, x9],[10, x10],[11, x11],[12, x12],[13, x13],[14, x14],[15, x15],[16, x16],[17, x17],[18, x18],[19, x19],[20, x20],[21, x21],[22, x22],[23, x23],[24, x24],[25, x25],[26, x26],[27, x27],[28, x28],[29, x29]], x);
f2 := solve(f=y,x);
area1 := int(f, y=0..1);
with(student):
area2 := trapezoid(f2[1], x = 0..1);
with(CodeGeneration):
CSharp(area1, resultname = "area1");
CSharp(area2, resultname = "area2");

i find area2 has

Warning, the function names {RootOf, Sum} are not recognized in the target language
Warning, precedence for Range unspecified
Warning, cannot translate range
area2 = RootOf((System.Double) (19276689540529530246975515949293568 * x3 - 2626509155780373903082144116707328 * x2 + 239680950855919251544490932629504 * x1 -

## Polynomial simplifications...

In the process of simplification I have the following multi-variable polynomial:

y:=-8*C*d1^2*(-2+d1)*(-1+d1)^3*r*L*R^3+(d1^4*(-2+d1)^2*L^2-4*C*(-2+d1)*(4*d1^3-13*d1^2+16*d1-8)*(-1+d1)^2*r^2*L+4*C^2*(-2+d1)^2*(-1+d1)^4*r^4)*R^2+(2*d1^4*(-2+d1)^2*r*L^2-2*C*(-2+d1)*(5*d1^3-24*d1^2+32*d1-16)*(-1+d1)^2*r^3*L+4*C^2*(-2+d1)^2*(-1+d1)^4*r^5)*R+d1^4*(-2+d1)^2*r^2*L^2-2*C*(-2+d1)*(d1^3-6*d1^2+8*d1-4)*(-1+d1)^2*r^4*L+C^2*(-2+d1)^2*(-1+d1)^4*r^6

This polynomial contains several (-2+d1), (-1+d1) terms with varying powers in each term. My question here is how to take out common terms and then form compact multi-variable polynomial (without having physical inspection).

MVC

## How do I filter a set?...

Dear Colleagues,

I am not sure if there exist a simple way to handle the issues I am facing. I am trying to obtain numeric roots for a polynomial f(x,a). I know for sure that there can be many roots depending on the value of parameter a. However, I cannot say for sure how many roots are possible for each value of parameter a. Some of these roots are complex numbers. Also, I need to choose only those roots that have following properties:

1. They are real.

2. f(x*,a) i.e., function value at a root is positive.

How do I solve f(x,a)=0 to store all roots in a set? Furthermore, how do I select and print roots that have the properties mentioned above? Is there a way to do filtering of a set specifying properties of the members of the set? Please suggest. Your help is highly appreciated.

Regards,

Omkar