# jacobiDC

Jacobi DC elliptic function

## Description

example

jacobiDC(u,m) returns the Jacobi DC Elliptic Function of u and m. If u or m is an array, then jacobiDC acts element-wise.

## Examples

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jacobiDC(2,1)
ans =
1

Call jacobiDC on array inputs. jacobiDC acts element-wise when u or m is an array.

jacobiDC([2 1 -3],[1 2 3])
ans =
1.0000    0.4197   -0.0056

Convert numeric input to symbolic form using sym, and find the Jacobi DC elliptic function. For symbolic input where u = 0 or m = 0 or 1,jacobiDC returns exact symbolic output.

jacobiDC(sym(2),sym(1))
ans =
1

Show that for other values of u or m, jacobiDC returns an unevaluated function call.

jacobiDC(sym(2),sym(3))
ans =
jacobiDC(2, 3)

For symbolic variables or expressions, jacobiDC returns the unevaluated function call.

syms x y
f = jacobiDC(x,y)
f =
jacobiDC(x, y)

Substitute values for the variables by using subs, and convert values to double by using double.

f = subs(f, [x y], [3 5])
f =
jacobiDC(3, 5)
fVal = double(f)
fVal =
0.9981

Calculate f to higher precision using vpa.

fVal = vpa(f)
fVal =
0.99805623285568333815968501058428

Plot the Jacobi DC elliptic function using fcontour. Set u on the x-axis and m on the y-axis by using the symbolic function f with the variable order (u,m). Fill plot contours by setting Fill to on.

syms f(u,m)
f(u,m) = jacobiDC(u,m);
fcontour(f,'Fill','on')
title('Jacobi DC Elliptic Function')
xlabel('u')
ylabel('m')

## Input Arguments

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Input, specified as a number, vector, matrix, or multidimensional array, or a symbolic number, variable, vector, matrix, multidimensional array, function, or expression.

Input, specified as a number, vector, matrix, or multidimensional array, or a symbolic number, variable, vector, matrix, multidimensional array, function, or expression.

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### Jacobi DC Elliptic Function

The Jacobi DC elliptic function is

dc(u,m) = dn(u,m)/cn(u,m)

where dn and cn are the respective Jacobi elliptic functions.

The Jacobi elliptic functions are meromorphic and doubly periodic in their first argument with periods 4K(m) and 4iK'(m), where K is the complete elliptic integral of the first kind, implemented as ellipticK.

## Version History

Introduced in R2017b