jacobi_cs( z , m )

The Jacobi cs function of z and parameter m in SageMath. Defined by

$\operatorname{cs}( u | m ) = \frac{ \operatorname{cn}( u | m ) }{ \operatorname{sn}( u | m ) }$

Note that all Jacobi elliptic functions in SageMath use the parameter rather than the elliptic modulus k, which is related to the parameter by $$m = k^2$$.

Plot on the real axis: