DLMF:

Figure 19.3.7 (See in context.)

Figure 19.3.7: $\mathop{K\/}\nolimits\!\left(k\right)$ as a function of complex $k^{2}$ for $-2\leq\realpart{(k^{2})}\leq 2$ , $-2\leq\imagpart{(k^{2})}\leq 2$ . There is a branch cut where $1<k^{2}<\infty$ .

Annotations:

Symbols:: $\mathop{K\/}\nolimits\!\left(k\right)$ : Legendre’s complete elliptic integral of the first kind, $\imagpart{}$ : imaginary part, $\realpart{}$ : real part and : real or complex modulus
Permalink:: http://dlmf.nist.gov/19.3.F7.mag
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