math模块学习

python的math模块方法：

acos(...)            # math.acos(0.5)*180/math.pi = 60.0
acos(x)
Return the arc cosine (measured in radians) of x.

acosh(...)
acosh(x)
Return the inverse hyperbolic cosine of x.

asin(...)            #math.asin(0.5)*180/math.pi = 30.0
asin(x)
Return the arc sine (measured in radians) of x.

asinh(...)
asinh(x)
Return the inverse hyperbolic sine of x.

atan(...)
atan(x)
Return the arc tangent (measured in radians) of x.

atan2(...)
atan2(y, x)
Return the arc tangent (measured in radians) of y/x.
Unlike atan(y/x), the signs of both x and y are considered.

atanh(...)
atanh(x)
Return the inverse hyperbolic tangent of x.

ceil(...)
ceil(x)
Return the ceiling of x as a float.
This is the smallest integral value >= x. 返回比x大的最小整数值

copysign(...)
copysign(x, y)
Return x with the sign of y.   y为正，则x返回为|x|；y为负，则x返回为-|x|

cos(...)
cos(x)
Return the cosine of x (measured in radians).

cosh(...)
cosh(x)
Return the hyperbolic cosine of x.

degrees(...)
degrees(x)
Convert angle x from radians to degrees. 把弧度转成角度

erf(...)
erf(x)
Error function at x.  误差函数

erfc(...)
erfc(x)
Complementary error function at x.

exp(...)
exp(x)
Return e raised to the power of x.

expm1(...)
expm1(x)
Return exp(x)-1.
This function avoids the loss of precision involved in the direct evaluation of exp(x)-1 for small x.

fabs(...)
fabs(x)
Return the absolute value of the float x. 返回浮点数的绝对值
factorial(...)
factorial(x) -> Integral
Find x!. Raise a ValueError if x is negative or non-integral.

floor(...)
floor(x)
Return the floor of x as a float.
This is the largest integral value <= x. 取比x小的最大的整数

fmod(...)
fmod(x, y)
Return fmod(x, y), according to platform C.  x % y may differ.

frexp(...)
frexp(x)
Return the mantissa and exponent of x, as pair (m, e).
m is a float and e is an int, such that x = m * 2.**e.
If x is 0, m and e are both 0.  Else 0.5 <= abs(m) < 1.0.

fsum(...)
fsum(iterable)
Return an accurate floating point sum of values in the iterable.
Assumes IEEE-754 floating point arithmetic.

gamma(...)
gamma(x)
Gamma function at x.

hypot(...)
hypot(x, y)
Return the Euclidean distance, sqrt(x*x + y*y).  #平方和的开方

isinf(...)
isinf(x) -> bool
Check if float x is infinite (positive or negative).

isnan(...)
isnan(x) -> bool
Check if float x is not a number (NaN).

ldexp(...)
ldexp(x, i)
Return x * (2**i).

lgamma(...)
lgamma(x)
Natural logarithm of absolute value of Gamma function at x.

log(...)
log(x[, base])
Return the logarithm of x to the given base.
If the base not specified, returns the natural logarithm (base e) of x.

log10(...)
log10(x)
Return the base 10 logarithm of x.

log1p(...)
log1p(x)
Return the natural logarithm of 1+x (base e).
The result is computed in a way which is accurate for x near zero.

modf(...)
modf(x)
Return the fractional and integer parts of x.  Both results carry the sign
of x and are floats.

pow(...)
pow(x, y)
Return x**y (x to the power of y).

radians(...)
radians(x)
Convert angle x from degrees to radians.

sin(...)
sin(x) 
Return the sine of x (measured in radians).

sinh(...)
sinh(x)
Return the hyperbolic sine of x.

sqrt(...)
sqrt(x)
Return the square root of x.

tan(...)
tan(x)
Return the tangent of x (measured in radians).

tanh(...)
tanh(x)
Return the hyperbolic tangent of x.

trunc(...)
trunc(x:Real) -> Integral 
Truncates x to the nearest Integral toward 0. Uses the __trunc__ magic method.

DATA:
e = 2.718281828459045
pi = 3.141592653589793

测试代码如下：

# -*- coding: utf-8 -*-
# @Author: yt
# @Date:   2018-05-16 09:23:07
# @Last Modified by:   yt
# @Last Modified time: 2018-05-16 14:26:53

import math

print ("degrees(math.pi/2)=",math.degrees(math.pi/2))

print ( 'tan(π/2) =',math.tan(math.pi/6) )#*180/math.pi
print ( 'atan(π/2) =',math.atan(0.5) )
print ( "atan2(1,1) =",math.degrees( math.atan2(1, 1) ) )

print ( 'sin(π/6) =',(math.sin(math.pi/6)))
print ( 'sin(π/6) =',math.cos(math.pi/6))

print ( "asin(1/2)=",math.degrees( math.asin(0.5) ) )
print ( "acos(1/2)=",math.degrees( math.acos(0.5) ) )

print ('sqrt(4) =',math.sqrt(4))         #求4的开平方
print ('pow(2,3) =',math.pow(2,3))       #求2的3次幂

print ('exp(2) =',math.exp(2))           #输出e的2次幂

print ('log(e) =',math.log(math.exp(1))) #对数运算
print ('log2(2) =',math.log2(2)) 
print ('log10(10) =',math.log10(10)) 

print ( "copysign(-2.0, 2)=",math.copysign(-2.0, 2) )         #copysign(X,Y)根据Y的正负，返回X
print ( "copysign(-2.0, -2)=",math.copysign(-2.0, -2) ) 

print ( "ceil(-2.5)=%d,ceil(2.5)=%d"%(math.ceil(-2.5),math.ceil(2.5))) #

print ( "fabs(x)=",math.fabs(-0.542) )

print ( "floor(x)=",math.floor(-0.542) )  #floor(x)取比x小的最大的整数

print ( "floor(x)=",math.hypot(2, 2) )    # =sqrt(x*x + y*y)

print ( "isnan(x)=",math.isnan(1) )

print ( "x*(2**i)=",math.ldexp(3, 2))     # ldexp(x, i) = x*(2**i)

运行结果：

图1