CONTENTS :- 1. DIFFERENTIAL EQUATIONS OF THE FIRST ORDER AND OF THE FIRST DEGRE A. DIFFERENTIAL EQUATIONS OF FIRST ORDER BUT NOT OF FIRST DEGREE B. SINGULAR SOLUTIONS AND TRAJECTORIES C. HOMOGENEOUS LINEAR EQUATIONS 2. LINEAR EQUATIONS WITH CONSTANT COEFFICIENTS 1. LINEAR EQUATIONS OF THE SECOND ORDER 2. ORDINARY SIMULTANEOUS DIFFERENTIAL EQUATIONS 3. TOTAL DIFFERENTIAL EQUATIONS 1. LINEAR PARTIAL DIFFERENTIAL EQUATIONS OF FIRS ORDER 2. NON-LINEAR PARTIAL DIFFERENTIAL EQUATIONS FOR FIRST ORDER 3. LINEAR PARTIAL DIFFERENTIAL EQUATINS WITH CONSTANT COEFFICENTS 1. SOLUTION IN SERIES