PHP 預定義數學常量
定義和用法
常量 | 值 | 描述 |
M_PI | 3.14159265358979323846 | 圓周率 Pi |
M_E | 2.7182818284590452354 | 尤拉數 e |
M_LOG2E | 1.4426950408889634074 | log2 e |
M_LOG10E | 0.43429448190325182765 | log10 e |
M_LN2 | 0.69314718055994530942 | loge 2 |
M_LN10 | 2.30258509299404568402 | loge 10 |
M_PI_2 | 1.57079632679489661923 | pi/2 |
M_PI_4 | 0.78539816339744830962 | pi/4 |
M_1_PI | 0.31830988618379067154 | 1/pi |
M_2_PI | 0.63661977236758134308 | 2/pi |
M_SQRTPI | 1.77245385090551602729 | sqrt(pi) |
M_2_SQRTPI | 1.12837916709551257390 | 2/sqrt(pi) |
M_SQRT2 | 1.41421356237309504880 | sqrt(2) |
M_SQRT3 | 1.73205080756887729352 | sqrt(3) |
M_SQRT1_2 | 0.70710678118654752440 | 1/sqrt(2) |
M_LNPI | 1.14472988584940017414 | loge(pi) |
M_EULER | 0.57721566490153286061 | 尤拉常數 |
PHP_ROUND_HALF_UP | 1 | 向上取整 |
PHP_ROUND_HALF_DOWN | 2 | 向下取整 |
PHP_ROUND_HALF_EVEN | 3 | 四捨六入五取偶 |
PHP_ROUND_HALF_ODD | 4 | 四捨六入五取奇 |
NAN | NAN | 非數字 |
INF | INF | 無窮大 |
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