Exponential interpolate y1 and y2 with mu normalized [0, 1]:
abjad> from abjad.tools import mathtools
abjad> mathtools.interpolate_exponential(0, 1, 0.5, 4)
0.0625
Set exp equal to the exponent of interpolation.
Return float.
Changed in version 2.0: renamed interpolate.exponential() to mathtools.interpolate_exponential().