notes on bash formula compilation for excel

#!/bin/bash
# 2d two points interpolation
echo 'interp($xi;$x1;$x2;$y1;$y2)' | sed -e 's%interp(\([^;]\+\);\([^;]\+\);\([^;]\+\);\([^;]\+\);\([^;]\+\))%И(\1>\2;\1<=\3)*((\1-\2)/(\3-\2)*(\5-\4)+\4)%g'
echo 'interp(A1;3;4;20;30)' | sed -e 's%interp(\([^;]\+\);\([^;]\+\);\([^;]\+\);\([^;]\+\);\([^;]\+\))%И(\1>\2;\1<=\3)*((\1-\2)/(\3-\2)*(\5-\4)+\4)%g'
echo 'interp(A1;0;1;20;30)+interp(A1;1;2;30;70)' | sed -e 's%interp(\([^;]\+\);\([^;]\+\);\([^;]\+\);\([^;]\+\);\([^;]\+\))%И(\1>\2;\1<=\3)*((\1-\2)/(\3-\2)*(\5-\4)+\4)%g'