HP 33s Owner's Manual page 194

Line E0004 sets flag 1 so that line W0011 takes the natural log of the
Y–input for an Exponential–model curve.
Lines P0003 and P0004 set both flags so that lines W0007 and W0011
take the natural logarithms of both the X– and Y–inputs for a Power–model
curve.
Note that lines S0003, S0004, L0004, and E0003 clear flags 0 and 1 to ensure
that they will be set only as required for the four curve models.
13–12
Programming Techniques
File name 33s-E-Manual-1008-Publication(1st).doc
Printed Date : 2003/10/8
Page : 386
Size : 13.7 x 21.2 cm