cool math homework assignment

Well you can move this to whatever board you want. Anyway I'm taking a course called 'engineering mathematics.' It's kind of the equivalent of a linear algebra course. My professor is an eccentric old lady that is way too smart to teach math to humans.

Our assignment over the weekend was to write in excel a command to evaluate the series for 'e' and 'pi' and to see how many terms in the series it took to get a certain number of decimal places accuracy. She suggested trying a couple of hundred terms, so of course I wrote a program that evaluates PI using 50 million terms. Kind of neat. Here are the results, the series for 'e' converged pretty quickly, not true for PI.

Quote:

E after 20 terms in the series: 2.718281828459045500000000000000

PI after 1000 terms in series: 3.142593654340044100000000000000

PI after 50000000 terms in series: 3.141592673590250900000000000000

Here's the program for it

Code:

`#include <iostream>`

#include <fstream>

#include <math.h>

using namespace std;

double factorial(double input)

{

if(input > 0)

return input * factorial(input-1);

else return 1;

}

double e_term(double which_term)

{

return 1.0 / (factorial(which_term));

}

double pi_term(double which_term)

{

int i_term;

_asm

{

fld which_term;

fistp i_term;

}

double sgn = pow(-1.0,i_term+1);

double denom = 1.0 / ((2.0 * which_term)-1);

return 4 * sgn * denom;

}

int main(void)

{

std::ofstream fout;

fout.open("results.txt");

fout.precision(50);

cout.precision(50);

double summation = 0.0;

for(double which_term = 0; which_term < 20; ++which_term)

{

summation += e_term(which_term);

fout << summation << "\n";

}

fout << "\n\n\n\n\n\n\n";

summation = 0;

for(which_term = 1; which_term < 1000; ++which_term)

{

summation += pi_term(which_term);

}

cout << "PI after 1000 terms in series: " << summation << "\n";

fout << "\nPI after 1000 terms in series: " << summation << "\n\n";

summation = 0;

for(which_term = 1; which_term < 50000000; ++which_term)

{

summation += pi_term(which_term);

}

cout << "PI after 50000000 terms in series: " << summation << "\n";

fout << "\nPI after 50000000 terms in series: " << summation << "\n\n";

return 0;

}