Blog Entry © Thursday, May 22, 2025, Baseball Ballistics with Simple Drag Computation by James Pate Williams, Jr.

// https://phys.libretexts.org/Bookshelves/University_Physics/Physics_(Boundless)/3%3A_Two-Dimensional_Kinematics/3.3%3A_Projectile_Motion

#pragma once

class ClassicalBallistics
{
public:
	ClassicalBallistics(void);
	~ClassicalBallistics(void);
	// analytical formula for maximum height
	double H(double V0, double theta0, double g);
	// analytical formula for flight time
	double T(double H, double g);
	// analytical formula for velocity at apex
	double Va(double V0, double theta0);
	// analytical formula for the range
	double L(double Va, double T);
	// analytical formula for time to apex
	double ta(double T);
	// analytical formula for range to apex
	double xa(double L);
	double xa(double H, double L, double theta0);
	double Theta1(double theta0);
	double Theta1(double H, double L, double xa);
	double ClassicalBallistics::V1(double V0);
};

#include "StdAfx.h"
#include "ClassicalBallistics.h"
#include <math.h>

ClassicalBallistics::ClassicalBallistics(void)
{
}
ClassicalBallistics::~ClassicalBallistics(void)
{
}
// analytical formula for maximum height
double ClassicalBallistics::H(double V0, double theta0, double g)
{
	double V02 = V0 * V0, sinTheta0 = sin(theta0);
	double sinTheta02 = sinTheta0 * sinTheta0;

	return V02 * sinTheta02 / (g * 2.0);
}
// analytical formula for flight time
double ClassicalBallistics::T(double H, double g)
{
	return 2.0 * sqrt(2.0 * H / g);
}
// analytical formula for velocity at apex
double ClassicalBallistics::Va(double V0, double theta0)
{
	double cosTheta0 = cos(theta0);
	double V02 = V0 * V0;

	return V0 * cosTheta0;
}
// analytical formula for the range
double ClassicalBallistics::L(double Va, double T)
{
	return Va * T;
}
// analytical formula for time to apex
double ClassicalBallistics::ta(double T)
{
	return 0.5 * T;
}
// analytical formula for range to apex
double ClassicalBallistics::xa(double L)
{
	return 0.5 * L;
}
double ClassicalBallistics::xa(double H, double L, double theta0)
{
	return sqrt(L * H / tan(theta0));
}
double ClassicalBallistics::Theta1(double theta0)
{
	return -theta0;
}
double ClassicalBallistics::Theta1(double H, double L, double xa)
{
	return atan(L * H / pow(L - xa, 2.0));
}
double ClassicalBallistics::V1(double V0)
{ 
	return V0;
}

// http://www.lajpe.org/sep13/04-LAJPE-782_Chudinov.pdf

#pragma once

const double g = 9.81;
// accleration due to gravity in Metric (SI) Units
const double k = 0.000625;
// k is typical for a baseball

class DragBallistics
{

public:

	DragBallistics(void);
	~DragBallistics(void);
    double f(double theta);
    // analytical formula for maximum height
    double H(double V0, double theta0, double g, double k);
    // analytical formula for flight time
    double T(double H, double g);
    // analytical formula for velocity at apex
    double Va(double V0, double theta0, double k);
    // analytical formula for the range
	double L(double Va, double T);
    double ta(double H, double T, double Va, double k);
    double xa(double H, double L, double theta0);
    double Theta1(double H, double L, double xa);
    double V1(double V0, double theta0, double theta1, double k);
};

#include "StdAfx.h"
#include "DragBallistics.h"
#include <math.h>

DragBallistics::DragBallistics(void)
{
}
DragBallistics::~DragBallistics(void)
{
}
double DragBallistics::f(double theta)
{
	double pi = 4.0 * atan(1.0);
	double sinTheta = sin(theta), cosTheta = cos(theta),
		cosTheta2 = cosTheta * cosTheta;
    return (sinTheta / cosTheta2) + log(tan(0.5 * theta + pi / 4.0));
}
// analytical formula for maximum height
double DragBallistics::H(double V0, double theta0, double g, double k)
{
	double V02 = V0 * V0, sinTheta0 = sin(theta0),
		sinTheta02 = sinTheta0 * sinTheta0;
    return V02 * sinTheta02 / (g * (2.0 + k * V02 * sinTheta0));
}
// analytical formula for flight time
double DragBallistics::T(double H, double g)
{
	return 2.0 * sqrt(2.0 * H / g);
}
// analytical formula for velocity at apex
double DragBallistics::Va(double V0, double theta0, double k)
{
	double pi = 4.0 * atan(1.0);
	double cosTheta0 = cos(theta0), cosTheta02 = cosTheta0 * cosTheta0;
    double V02 = V0 * V0, sinTheta0 = sin(theta0);
    return V0 * cosTheta0 / sqrt(1.0 + k * V02 * (sinTheta0 + 
		cosTheta02 * log(tan(0.5 * theta0 + pi / 4.0))));
}
// analytical formula for the range
double DragBallistics::L(double Va, double T)
{
	return Va * T;
}
double DragBallistics::ta(double H, double T, double Va, double k)
{
	return 0.5 * (T - k * H * Va);
}
double DragBallistics::xa(double H, double L, double theta0)
{
	return sqrt(L * H / tan(theta0));
}
double DragBallistics::Theta1(double H, double L, double xa)
{
	return -atan(L * H / pow(L - xa, 2.0));
}
double DragBallistics::V1(double V0, double theta0, double theta1, double k)
{
	double V02 = V0 * V0;
    double sinTheta0 = sin(theta0), cosTheta0 = cos(theta0),
		cosTheta02 = cosTheta0 * cosTheta0;
    return V0 * cosTheta0 / (cos(theta1) * sqrt(1.0 + k * 
		V02 * cosTheta02 * (f(theta0) - f(theta1))));
}

// BaseballBallisticsWin32Console.cpp
// Translated from August 2017 C# application
// May 21, 2025 (c) James Pate Williams, Jr.

#include "stdafx.h"
#include "ClassicalBallistics.h"
#include "DragBallistics.h"
#include <iomanip>
#include <iostream>
#include <math.h>

void PrintResults(char title[],
				  double H, double T, double Va,
				  double L, double Ta, double xa,
				  double Theta1, double V1)
{
	std::cout << title << std::endl;
	std::cout << std::fixed << std::setprecision(2);
	std::cout << "H      = " << H << std::endl;
	std::cout << "T      = " << T << std::endl;
	std::cout << "Va     = " << Va << std::endl;
	std::cout << "L      = " << L << std::endl;
	std::cout << "Ta     = " << Ta << std::endl;
	std::cout << "xa     = " << xa << std::endl;
	std::cout << "theta1 = " << Theta1 << std::endl;
	std::cout << "V1     = " << V1 << std::endl;
}

int _tmain(int argc, _TCHAR* argv[])
{
	while (true)
	{
		char line[128] = { };
		std::cout << "V0 (m / s) or 0 to quit: ";
		std::cin.getline(line, 128);
		double V0 = atof(line);
		if (V0 == 0)
		{
			break;
		}
		std::cout << "Enter angle in degrees: ";
		std::cin.getline(line, 128);
		double theta0 = atof(line);
		double pi = 4.0 * atan(1.0);
		theta0 *= pi / 180.0;
		ClassicalBallistics cBall;
		DragBallistics dBall;
		double cH = cBall.H(V0, theta0, g);
        double dH = dBall.H(V0, theta0, g, k);
        double cT = cBall.T(cH, g);
        double dT = dBall.T(dH, g);
        double cVa = cBall.Va(V0, theta0);
        double dVa = dBall.Va(V0, theta0, k);
        double cL = cBall.L(cVa, cT);
        double dL = dBall.L(dVa, dT);
        double cta = cBall.ta(cT);
        double dta = dBall.ta(dH, dT, dVa, k);
        double cxa = cBall.xa(cL);
        double dxa = dBall.xa(dH, dL, theta0);
        double cTheta1 = 180.0 * cBall.Theta1(theta0) / pi;
        double dTheta1 = 180.0 * dBall.Theta1(dH, dL, dxa) / pi;
        double cV1 = cBall.V1(V0);
        double dV1 = dBall.V1(V0, theta0, pi * dTheta1 / 180.0, k);
		PrintResults("Classical Ballistics",
			cH, cT, cVa, cL, cta, cxa, cTheta1, cV1);
		PrintResults("Drag Ballistics",
			dH, dT, dVa, dL, dta, dxa, dTheta1, dV1);
	}
	return 0;
}

Blog Entry © Wednesday, May 21, 2025, Backpropagation Artificial Neural Network Experiments by James Pate Williams, Jr.

Learning a Simple Function Using an Artificial Backpropagation Neural Network © Wednesday, May 14, 2025, by James Pate Williams, Jr., BA, BS, Master of Software Engineering, and PhD Computer Science

Blog Entry © Monday, May 12, 2025, by James Pate Williams, Jr., BA Chemistry, BS Computer Science, Master of Software Engineering, PhD Computer Science Two Minor Catastrophes

Blog Entry (c) Friday, April 11, 2025, by James Pate Williams, Jr. Multiplication and Division of Finite Power Series

x = 0.25
N = 5
Series Cosine(x)  = 0.968912421711
C++ cos(x)        = 0.968912421711
Series sine(x)    = 0.247403959255
C++ sin(x)        = 0.247403959255
Series Tangent(x) = 0.255341921221
C++ tan(x)        = 0.255341921221
Series sin(2x)    = 0.479425538604
C++ sin(2x)       = 0.479425538604
C++ 2sin(x)cos(x) = 0.479425538604
End app ? y = yes = n
x = 0.5
N = 5
Series Cosine(x)  = 0.877582561890
C++ cos(x)        = 0.877582561890
Series sine(x)    = 0.479425538604
C++ sin(x)        = 0.479425538604
Series Tangent(x) = 0.546302489844
C++ tan(x)        = 0.546302489844
Series sin(2x)    = 0.841470984807
C++ sin(2x)       = 0.841470984808
C++ 2sin(x)cos(x) = 0.841470984808
End app ? y = yes = y
x = 0.75
N = 5
Series Cosine(x)  = 0.731688868808
C++ cos(x)        = 0.731688868874
Series sine(x)    = 0.681638760020
C++ sin(x)        = 0.681638760023
Series Tangent(x) = 0.931596460023
C++ tan(x)        = 0.931596459944
Series sin(2x)    = 0.997494986509
C++ sin(2x)       = 0.997494986604
C++ 2sin(x)cos(x) = 0.997494986604
End app ? y = yes = n
 
x = 1.00
N = 5
Series Cosine(x)  = 0.540302303792
C++ cos(x)        = 0.540302305868
Series sine(x)    = 0.841470984648
C++ sin(x)        = 0.841470984808
Series Tangent(x) = 1.557407730344
C++ tan(x)        = 1.557407724655
Series sin(2x)    = 0.909297423159
C++ sin(2x)       = 0.909297426826
C++ 2sin(x)cos(x) = 0.909297426826
End app ? y = yes = n
x = 1.25
N = 5
Series Cosine(x)  = 0.315322332275
C++ cos(x)        = 0.315322362395
Series sine(x)    = 0.948984616456
C++ sin(x)        = 0.948984619356
Series Tangent(x) = 3.009569952151
C++ tan(x)        = 3.009569673863
Series sin(2x)    = 0.598472085108
C++ sin(2x)       = 0.598472144104
C++ 2sin(x)cos(x) = 0.598472144104
End app ? y = yes = n
x = 1.50
N = 5
Series Cosine(x)  = 0.070736934117
C++ cos(x)        = 0.070737201668
Series sine(x)    = 0.997494955682
C++ sin(x)        = 0.997494986604
Series Tangent(x) = 14.101472846329
C++ tan(x)        = 14.101419947172
Series sin(2x)    = 0.141119469924
C++ sin(2x)       = 0.141120008060
C++ 2sin(x)cos(x) = 0.141120008060
End app ? y = yes = y

// DivMulPowerSeries.cpp (c) Tuesday, April 8, 2025
// by James Pate Williams, Jr.
// https://math.libretexts.org/Bookshelves/Calculus/Calculus_(OpenStax)/10%3A_Power_Series/10.02%3A_Properties_of_Power_Series
// https://en.wikipedia.org/wiki/Formal_power_series

#include <iostream>
#include <iomanip>
#include <string>
#include <vector>

std::vector<double> Multiplication(
	std::vector<double> c,
	std::vector<double> d,
	int N) {
	std::vector<double> e(N + 1);

	for (int n = 0; n <= N; n++) {
		double sum = 0.0;

		for (int k = 0; k <= n; k++) {
			sum += c[k] * d[n - k];
		}

		e[n] = sum;
	}

	return e;
}

std::vector<double> Division(
	std::vector<double> a,
	std::vector<double> b,
	int N) {
	double a0 = a[0];
	std::vector<double> c(N + 1);

	for (int n = 0; n <= N; n++) {
		double sum = 0.0;

		for (int k = 1; k <= n; k++) {
			sum += a[k] * c[n - k];
		}

		c[n] = (b[n] - sum) / a0;
	}

	return c;
}

double Factorial(int n) {
	double nf = 1.0;

	for (int i = 2; i <= n; i++) {
		nf *= i;
	}

	return nf;
}

std::vector<double> Cosine(double x, int N, double& fx) {
	std::vector<double> series(N + 1);

	fx = 0.0;

	for (int n = 0; n <= N; n++) {
		int argument = 2 * n;
		double coeff = pow(-1, n) / Factorial(argument);
		series[n] = coeff;
		fx += coeff * pow(x, argument);
	}

	return series;
}

std::vector<double> Sine(double x, int N, double& fx) {
	std::vector<double> series(N + 1);
	
	fx = 0.0;

	for (int n = 0; n <= N; n++) {
		int argument = 2 * n + 1;
		double coeff = pow(-1, n) / Factorial(argument);
		series[n] = coeff;
		fx += coeff * pow(x, argument);
	}

	return series;
}

std::vector<double> Tangent(double x, int N, double& fx) {
	double fc = 0.0, fs = 0.0;
	std::vector<double> seriesC = Cosine(x, N, fc);
	std::vector<double> seriesS = Sine(x, N, fs);
	std::vector<double> seriesT = Division(seriesS, seriesC, N);
	fx = fs / fc;

	return seriesT;
}

std::vector<double> Sine2x(double x, int N, double& fx) {
	double fc = 0.0, fs = 0.0;
	std::vector<double> seriesC = Cosine(x, N, fc);
	std::vector<double> seriesS = Sine(x, N, fs);
	std::vector<double> series2 = Multiplication(seriesS, seriesC, N);
	fx = 2.0 * fs * fc;

	return series2;
}

int main()
{
	while (true) {
		char line[128] = { };
		std::cout << "x = ";
		std::cin.getline(line, 127);
		std::string str1(line);
		double x = std::stod(str1);
		std::cout << "N = ";
		std::cin.getline(line, 127);
		std::string str2(line);
		int N = std::stoi(str2);
		double cx = 0.0, sx = 0.0, tx = 0.0, xx = 0.0;
		std::vector<double> cSeries = Cosine(x, N, cx);
		std::vector<double> sSeries = Sine(x, N, sx);
		std::vector<double> tSeries = Tangent(x, N, tx);
		std::vector<double> xSeries = Sine2x(x, N, xx);
		std::cout << std::fixed << std::setprecision(12);
		std::cout << "Series Cosine(x)  = " << cx << std::endl;
		std::cout << "C++ cos(x)        = " << cos(x) << std::endl;
		std::cout << "Series sine(x)    = " << sx << std::endl;
		std::cout << "C++ sin(x)        = " << sin(x) << std::endl;
		std::cout << "Series Tangent(x) = " << tx << std::endl;
		std::cout << "C++ tan(x)        = " << tan(x) << std::endl;
		std::cout << "Series sin(2x)    = " << xx << std::endl;
		std::cout << "C++ sin(2x)       = " << sin(x + x) << std::endl;
		std::cout << "C++ 2sin(x)cos(x) = " << 2.0 * sin(x) * cos(x);
		std::cout << std::endl;
		std::cout << "End app ? y = yes = ";
		std::cin.getline(line, 127);

		if (line[0] == 'Y' || line[0] == 'y') {
			break;
		}
	}

	return 0;
}

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