最简洁的表达式：(lnx)'=1/x，大道至简，大道自然。
10 用c代码近似计算e值10.1 用级数1 1/1! 1/2! 1/3! 1/4! 1/5! 1/6! ... 1/n! ...近似e值
#include "stdafx.h"
#include <math.h>
int factorial(int j)
{
int sum;
if(j == 0)
sum = 1;
if(j == 0)
sum = 1;
else
sum = j * factorial(j-1);
return sum;
}
void main()
{
int i;
double sum1 = 0.0;
for(i=0;i<=12;i ){
sum1 = sum1 (1.0/factorial(i));
}
printf("0: %d %d %f ",i,factorial(i),sum1);
}
//运行结果：0: 13 1932053504 2.718282
10.2 用公式lim(1 1/n)^n(n→∞)近似e值
#include "stdafx.h"
#include <math.h>
void main()
{
int i;
double sum1,sum2;
for(i=1;i<=10;i ){
sum1 = (1.0 (1.0/i));
sum2 = pow(sum1,i);
printf("%d %f ",i,sum2);
}
printf(" ");
for(i=90;i<=100;i ){
sum1 = (1.0 (1.0/i));
sum2 = pow(sum1,i);
printf("%d %f ",i,sum2);
}
printf(" ");
for(i=99990;i<=100000;i ){
sum1 = (1.0 (1.0/i));
sum2 = pow(sum1,i);
printf("%d %f ",i,sum2);
}
printf(" ");
}
1 2.000000
2 2.250000
3 2.370370
4 2.441406
5 2.488320
6 2.521626
7 2.546500
8 2.565785
9 2.581175
10 2.593742
90 2.703332
91 2.703495
92 2.703654
93 2.703810
94 2.703962
95 2.704112
96 2.704258
97 2.704401
98 2.704542
99 2.704679
100 2.704814
99990 2.718268
99991 2.718268
99992 2.718268
99993 2.718268
99994 2.718268
99995 2.718268
99996 2.718268
99997 2.718268
99998 2.718268
99999 2.718268
100000 2.718268
－End－
