## 155 Reputation

12 years, 150 days

## Substract powers in a series...

Hi,

I tried to obtain power of a series. I have the following input

***

assume(c<-10);
eq1:=2*x^a*y^b*(x+y)^c+3*x^(a+1)*y^(b+1)*(x+y)^(c+1);

f1:=map(t -> `if`(match(t = d*x^e*y^f*(x+y)^g, x, 's'), subs(s,e), NULL),
convert(eq1, list));

f2:=map(t -> `if`(match(t = d*x^e*y^f*(x+y)^g, y, 's'), subs(s,f), NULL),
convert(eq1, list));

f3:=map(t -> `if`(match(t = d*x^e*y^f*(x+y)^g, x+y, 's'), subs(s,g), NULL),
convert(eq1, list));

print(f1);

****

The output is

****

a b c (a + 1) (b + 1) (c + 1)
2 x y (x + y) + 3 x y (x + y)
[]
[]
Error, (in unknown) invalid input: match expects its 2nd argument, vv, to be of type {name, set(name)}, but received x+y
[]

***

How to get the correct powers of x, y, and (x+y)? Since the power of x+y is negative, it cannot be absorbed into x and y.

Thank you!

## extract coefficient in multivariate case...

Maple 12

Hi,

I have an expression as p in the following. I would like to extract the coeffient with x^n*y^m and x^(n+2)*y^(m+2), however, coeff comand does not work...

***

p:=3*x^n*y^m+4*x^(n+2)*y^(m+2)+k*x^(n+2)*y^(m+2);
coeff(p,x,n);

***

gives me

***

n m (n + 2) (m + 2) (n + 2) (m + 2)
3 x y + 4 x y + k x y
/ n m (n + 2) (m + 2) (n + 2) (m + 2) \
coeff\3 x y + 4 x y + k x y , x, n/

***

What is the correct command to get the coefficients? Thank you very much

## Saving the solution from fsolve...

Maple 16

Hello,

I have a question. Consider

fsolve(x^2+3*x+1=3, x);

I want to save the two roots into two variables. What kind of commend shall I use?

P.S. My further aim comes from solving an equation without analytical solution. Therefore I cannot plug in the solution formula.

## Pointplot with different colors...

Maple 10

I have 20 datapoints in two groups. I may name them as f[1],...,f[10];g[1],...,g[10]. f[1]:=[1.2,3.5] etc

I would like to plot these 20 points

(1) in one plot

(2) f[1]~f[10] in one color; g[1]~g[10] in another color.

I checked http://www.maplesoft.com/support/help/Maple/view.aspx?path=plots%2fpointplot

and did not get the point :(

Do you any suggestion what can I do to realize the aims (1) and (2)?

Thank you very much in advance!

Maple 10

Hi,

I tried to use generated random as following

***

for j from 1 to 5 do
c:=rand(0..1):
d:=c();
print(`random number`,c(),d);

if c()=1 then

print(`Y`)
else
print(`N`);
end if;
end do:

***

The output is

****

random number, 1, 0

Y

random number, 1, 1

Y

random number, 1, 1

N

random number, 1, 1

N

random number, 0, 0

N

****

Why the output numbers in one line are different? And Using "if" sentence seems do not correspond to the printed "c()" value..

Thank you very much in advance!

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