How to get the only solution x = (1/6)*sqrt(114)*a of this equation?
restart;
with(Student:-MultivariateCalculus);
u := `<,>`(-(1/4)*a, -(1/12)*sqrt(3)*a, -x);
v := `<,>`(-(1/2)*a, (1/6)*sqrt(3)*a, (1/2)*x);
`assuming`([solve(Angle(u, v) = arccos(2*sqrt(26)*(1/13)), x)], [And(a > 0, x > 0)])

Experts,

I have a series as follows: 

b := (sum((x[i]-xbar)^3, i = 1 .. n))/(n*[(sum((x[i]-xbar)^2, i = 1 .. n))/(n-1)]^1.5)

(b is skewness of x)

Taking the derivatives:

c1:=diff(b, xbar);

c2:=diff(b, x[i]);
 

now I want to evaluate c1 and c2 with a matrix input:

x:=<<0.556960605000000>,<3.39039994000000>,<2.09005200300000>,<0.645104568000000>,<5.31340491600000>,<3.32743462200000>,<0.635452131000000>,<1.56878297000000>,<0.282764039000000>,<1.02862059900000>,<3.14927606700000>,<0.654644768000000>,<1.30502450500000>,<2.13887537900000>,<2.11803658900000>,<7.29488570500000>,<0.478693554000000>>

where xbar is the mean value of x

Can you please help me

Thanks

i have two expressions. S1 and S2 are functions of sigma and tau. but i need derivative of sigma and tau with respect to S1 and S2. what should i do ? could any one help?


 

Download chain_rule_derivative.mw

Hey guys im still quite new to maple so bear with me on this one. 

Im trying to make it so when i press a button an some mathcontainers are going though some if statements, and then printing out the answer.

Heres the code 

use DocumentTools in 

Do(indkomst = %MathContainer2);
Do(fradrag = %MathContainer4);

if indkomst <= 44000 then 
    
    Do(%MathContainer3 = 0.08*indkomst);

elif 44000 < 0.92*indkomst and indomst <= 44000+fradrag then
    
    Do(%MathContainer3 = 0.08*indkomst + 0.0908*(0.92*indkomst - 44000));

elif 44000+fradrag < 0.92*indkomst and indkomst <= 467300 then

    Do(%MathContainer3 = 0.08*indkomst + 0.0908*(0.92*indkomst - 44000) + 0.276*(0.92*indkomst - 44000 - fradrag));

elif 0.92*indkomst > 467300 then

    Do(%MathContainer3 = 0.08*indkomst + 0.0908*(0.92*indkomst - 44000) + 0.276*(0.92*indkomst - 44000 - fradrag) + 0.15*(0.92*indkomst - 467300));
    
end if;

end use; 
 

It correctly chooses what statement to use, but it just cant determine if its true or false, how do i fix this?

I'm trying to solve this to set of equations :

EQ1:=-1958143.922*k*wr+2468.8339*k^3*wr-0.9481118254e16*k^2-114000.8376*k^4:

EQ2 :=-1186578.220*R*k^2*wr-312683.0293*k^5-288960.9621*k^3*R:

using a loop for different value of R in the range this range (wr=0..10,k=0..10)

eqns:={EQ1,EQ2}:
for i from 1 by 1 to 101 do R:=(i-1):S:=fsolve(eqns,{k, wr},{wr=0..10,k=0..10}):v(i):=(subs(S,(wr)));w(i):=(subs(S,(k)))end do:

but i get this instead :

Error, invalid input: subs received fsolve({-312683.0293*k^5, -1958143.922*k*wr+2468.8339*k^3*wr-0.9481118254e16*k^2-114000.8376*k^4}, {k, wr}, {k = 0 .. 10, wr = 0 .. 10}), which is not valid for its 1st argument

is there another way to solves this equations more easly .

Hello guys, 

I have a probelm with computing an integral by maple. I dont know why maple cannot compute.

integral.mw

Thank you for your attention

Best

I do not understand why Maple can simplify this expression below when told that n is integer and also positive using a "," to separate the assumptions, but does simpify the same expression when using "and" to build the assumptions.

Here is an example

restart;
result:=int(x*cos(n*Pi/5*x),x=0..5)
simplify(result) assuming n::integer and n>0

But this works

simplify(result) assuming n::integer, n>0

What are the semantic differences between writing assuming "n::integer and n>0" and "n::integer,n>0" ? I thought these would be the same, but clearly they are not.

Maple 2019.1 on windows.

1/0;
Error, numeric exception: division by zero
lastexception;
            0, "numeric exception: division by zero"
lastexception; # ???
            Typesetting:-Typeset, "invalid input: %1 expects %2 arguments, but received %3", type, 2, 3

So, printing lastexception produces a new error!
When typesetting=standard, it's OK.

Hello my Maple friends! :)
I was wondering if there is any command in Maple that can help me find the equation of a surface from it´s parametric form and the other way around, a parametric form from a surface equation!
For example, if
x :=(s, t) -> s cos(t)
y :=(s, t) -> s sin(t)
z :=(s, t) -> s^2

then S: x^2+y^2=z

Thank you for your help.
English is not my mother tongue; please excuse any errors on my part.

I have two data sets (time series) that appear to have similar profiles and am looking to find a way to establish a correlation measure. The linear (Pearson) coefficient is around 0.89, but since this particular function is nonlinear, can anyone suggest a method or routine that can be used to obtain this correlation?

Thank you!

Correlation.mw

Hello, would you please help with this problem

 I need to solve the system using polynomial coefficients

thank you 

Download dsolve.mwdsolve.mw

Download rand.mw

Download SHAFEEG2.mwSHAFEEG2.mw

Hey.. AoA,
How to combine a specific rows of two different Matrix?

Hi, I have a procedure named f1. In it, it calls another procedure f couple of times. procedure f does not have recursive calls implemented.

I have no idea what caused the error. Could anyone give a hint?

Thanks a million in advance,

Best,

Jie