How is it possible that Mathematica doesn't recognize it's own definitions of special functions ? I tried as input:
Integrate[Cosh[I2t]/E^(6 Cosh[t]), {t, 0, Infinity}]
The above should give $K_{i2}(6)$ according to this. Unfortunately, it just happily reproduces my input, and leaves me ignorant of how it should have been phrased.
Does someone know how I could get Mathematica recognize to evaluate such input to something useful?
Moreover, when I plot
Plot[BesselK[2 I, z], {z, 0, 7}]
I get a graph, but when I evaluate
BesselK[2 I, 6]
again, Mathematica repeats my input.
I'm not really used to Mathematica, so sometimes I get this sort of frustrating output, Mathematica not understanding what I'm trying to say.
I2t
is treated as a single variable; put spaces in between variables that you intend to multiply. 2.BesselK[2 I, 6]
is an exact number without an apparently simpler closed form; to see an approximation, useN[]
:N[BesselK[2 I, 6]]
. $\endgroup$ – J. M.'s ennui♦ Jun 3 '15 at 0:17