GX only This library has two command: NW48, SL48 NW48 is a nonlineal and lineal system equation solver. Is fast, simple to use and, in most of case, can obtain a solution. Can operate with real and complex number. Supose that you have one equation's system like this: (This is the file E3.1 in the NW48.EXA directory) 'Av=-\PI(RL1,RC)/(HIB+RE1)' 'RCA=RE1+\PI(RC,RL1)' 'RCD=RE1+RC' 'ICQ=VCC/(RCA+RCD)' '-VCC+ICQ*RC+VCE+ICQ*RE1' '-VBB+RB*ICQ/\Gb+VBE+ICQ*RE1' '(R1+R2)*VBB=VCC*R1' 'HIB=.026/ABS(ICQ)' 'AI=-RB/(RB/\Gb+HIB+RE1)*RC/(RC+RL1)' 'RB=.1*\Gb*RE1' 'RB=\PI(R1,R2)' 'Vop=2*ABS(ICQ)*\PI(RC,RL1)' & 'Av=-10' | 'RC=1000' | 'RL1=1000' \ 'VCC=-12' | Known values 'VBE=-.7' / '\Gb=200' | This kind of system is common in electronics. Here \PI is the function parallel in the library ELECT.LIB. The symbol '&' separate the equation and the known values. You can change the known values how you like. The number of equation and the number of unknown must to be the same. If you have not known values, no problem, this is opcional. To run the program press NW48, write the equations in the first screen or copy E3.1 (or any other) into EQ and press NW48. In the second screen: VARS: List of unknown XO: List of inicial values (You can change it) TOL: Tolerance for Newton's Method (If zero don't use this method) TOL: Tolerance for Gradient's Method (If zero don't use this method) In general the tolerance for Gradient's Method is a large value like 2, 1, 0.5 etc. This method is only to find an inicial point for the Newton's Method. In most of case is not necesary. SL48 is a lineal system solver. You can write the equations in the same form that in the NW48. Only lineal system. Is very fast. Julio Mendoza, Universidad Santa Maria La Antigua Panama, Rep. of Panama. E-Mail: find Panama