Why are some coefficients negative when expanding a function in Legendre?

  • Thread starter Thread starter chenaiyy
  • Start date Start date
  • Tags Tags
    Function Legendre
chenaiyy
Messages
1
Reaction score
0
I get a series of Legendre expansion coefficients for a function. Then I compute the value of the function via expansion coefficients. As I want to whether the code is right or not, finally I expand the function in Legendre again. the result is almost same as before, but some coefficients is negative which are not exist before. I want to know why ?
The code are all fortran.
Thanks a lot!
 
Mathematics news on Phys.org
You'll have to show the code!
 

Thread 'What Exactly is Dirac’s Delta Function? - Insight'

Insights auto threads is broken atm, so I'm manually creating these for new Insight articles. In Dirac’s Principles of Quantum Mechanics published in 1930 he introduced a “convenient notation” he referred to as a “delta function” which he treated as a continuum analog to the discrete Kronecker delta. The Kronecker delta is simply the indexed components of the identity operator in matrix algebra Source: https://www.physicsforums.com/insights/what-exactly-is-diracs-delta-function/ by...
View full post »

Thread 'Fermat's Last Theorem'

Fermat's Last Theorem has long been one of the most famous mathematical problems, and is now one of the most famous theorems. It simply states that the equation $$ a^n+b^n=c^n $$ has no solutions with positive integers if ##n>2.## It was named after Pierre de Fermat (1607-1665). The problem itself stems from the book Arithmetica by Diophantus of Alexandria. It gained popularity because Fermat noted in his copy "Cubum autem in duos cubos, aut quadratoquadratum in duos quadratoquadratos, et...
View full post »

Thread 'Useless continued fraction for 1'

I'm interested to know whether the equation $$1 = 2 - \frac{1}{2 - \frac{1}{2 - \cdots}}$$ is true or not. It can be shown easily that if the continued fraction converges, it cannot converge to anything else than 1. It seems that if the continued fraction converges, the convergence is very slow. The apparent slowness of the convergence makes it difficult to estimate the presence of true convergence numerically. At the moment I don't know whether this converges or not.
View full post »

Similar threads

Kronecker Delta in Legendre Series
Replies
4
Views
2K
Coefficient Matching for different series
Replies
5
Views
2K
Legendre Polynomials & the Generating function
Replies
1
Views
3K
I Alternating Harmonic Numbers are cool, spread the word!
Replies
4
Views
2K
MATLAB Turning Fourier coefficients into an interpolated freq domain function
Replies
8
Views
2K
B Generating the formula for the coefficients of an alternating series
Replies
17
Views
4K
I Series Expansion of the Infinitesimal Spacetime Interval
Replies
22
Views
3K
Why do I keep getting friction coefficient as a negative?
Replies
17
Views
3K
I Solving simultaneous vector equations
Replies
11
Views
3K
Understanding the Legendre Recurrence Relation for Generating Functions
Replies
1
Views
2K

Hot Threads

Recent Insights

Back
Top