Apparatus for plotting the derivative of a function as a function of the independent variable

Claim 1

APPARATUS FOR PLOTTING THE DERIVATIVE OF A FUNCTION Y=F(X) AS A FUNCTION OF THE INDEPENDENT VARIABLE X, SAID APPARATUS COMPRISING: MEANS PROVIDING A FLAT SURFACE HAVING RECTANGULAR X AND Y DIRECTIONS DELINEATED REPRESENTAUPON WHICH SURFACE MAY BE PLACED A GRAPHICAL REPRESENTATION OF THE FUNCTION Y=F(X) PLOTTED IN AN X-Y RECTANGULAR COORDINATE SYSTEM WITH THE X AND Y AXES PARALLEL TO SAID X AND Y DIRECTIONS; A CURSOR SLIDABLE OVER SAID SURFACE AND HAVING AN INDEX POINT LOCATED ON A STRAIGHT INDEX LINE; SUPPORT MEANS ATTACHED TO SAID SURFACE AND TO SAID CURSOR SO AS TO PROVIDE A PIVOTAL AXIS FOR SAID CURSOR NORMAL TO SAID SURFACE, MOVABLE OVER SAID SURFACE AND INTERSECTING SAID INDEX LINE AT A POINT REMOVED FROM SAID INDEX POINT; MEANS FIXED RELATIVE TO SAID SURFACE AND ACTUATED BY SAID SUPPORT MEANS FOR PRODUCING A DIRECT VOLTAGE X'' PROPORTIONAL TO AND OF THE SAME SIGN AS THE DISPLACEMENT MEASURED IN SAID X DIRECTION OF SAID PIVOTAL AXIS FROM AN ADJUSTABLE X DIRECTION ZERO POSITION; TANGENT AND COSINE FUNCTION GENERATORS COUPLED TO SAID CURSOR AND ACTUATED BY ITS ROTATION ABOUT SAID PIVOTAL AXIS TO PRODUCE DIRECT VOLTAGES PROPORTIONAL TO AND OF THE SAME SIGN AS THE TANGENT AND THE COSINE OF THE ANGLE BETWEEN SAID INDEX LINE AND SAID X DIRECTION; A RECTANGULAR COORDINATE PLOTTER HAVING Y AND X INPUTS; MEANS FOR APPLYING SAID TANGENT VOLTAGE OF THE Y INPUT OF SAID PLOTTER; AND MEANS FOR ALGEBRAICALLY ADDING SAID COSINE VOLTAGE AND SAID X'' VOLTAGE AND FOR APPLYING THE SUM TO THE X INPUT OF SAID PLOTTER.