 (20S) and (21S) Numerical Derivative - Printable Version +- HP Forums (https://www.hpmuseum.org/forum) +-- Forum: HP Software Libraries (/forum-10.html) +--- Forum: General Software Library (/forum-13.html) +--- Thread: (20S) and (21S) Numerical Derivative (/thread-13000.html) (20S) and (21S) Numerical Derivative - Eddie W. Shore - 05-20-2019 12:58 PM Numerical Derivative f'(x0) ≈ ( f(x0 + h) - f(x0 - h) ) / ( 2*h ) x = point h = small change of x, example h = 0.0001 LBL A: Main Progam LBL F: f(X), where R0 acts as X Input variables: R1 = h R2 = point x0 Used variables: R0 = x (use R0 for f(x), LBL F) Calculated Variables: R3 = f'(x) Radians mode will be set. Program: Code: ``` 01  LBL A:  61,41A 02  RAD:  61,24 03  RCL 2:  22,2 04  +:  75 05  RCL 1:  22, 1 06  =:  74 07  STO 0:  21,0 08 XEQ F:  41,F 09  STO 3:  21, 3 10  RCL 2: 22,2 11 -:  65 12 RCL 1: 22,1 13 =:  74 14 STO 0: 21,0 15 XEQ F:  41,F 16 STO - 3:  21,65,3 17 2:  2 18 STO ÷ 3:  21,45,3 19  RCL 1:  22,1 20 STO ÷ 3: 21,45,3 21  RCL 3:  22,3 22 R/S:  26 23 LBL F:  61,41,F ... xx  RTN:  61,26  (end f(X) with RTN)``` Example: e^x * sin x LBL F RCL 0 e^x * RCL 0 SIN = RTN R1 = 0.0001 R2 = x0 = 0.03 Result: 1.060899867 R1 = 0.0001 R2 = x0 = 1.47 Result: 4.7648049