2.5中'math'模块的问题? [英] problem with the 'math' module in 2.5?
问题描述
>>来自math import *
>> sin(0 )
0.0
>> sin(pi)
1.2246063538223773e-016
>> sin(2 * pi)
-2.4492127076447545e-016
>> ; cos(0)
1.0
>> cos(pi)
-1.0
> > cos(2 * pi)
1.0
余弦函数工作正常,但我正在为正弦得到奇怪的答案。
这是一个错误吗?我做错了吗?
解决方案
Chris写道:
>来自数学导入*
sin(0)
0.0
> sin(pi)
1.2246063538223773e-016
> sin(2 * pi)
-2.4492127076447545e-016
> cos(0)
1.0
> cos(pi )
-1.0
> cos(2 * pi)
1.0
余弦函数工作正常,但我正在为正弦得到奇怪的答案。
这是一个错误吗?难道我做错了什么?
你认为2.4版本的答案是什么?
" Chris" < ch ********* @ gmail.comwrote:
> ;>>来自数学导入*
sin(0)
0.0
>>> sin(pi)
1.2246063538223773e-016
>>> sin(2 * pi)
-2.4492127076447545e-016
>>> cos(0)
1.0
>>> cos(pi)
-1.0
>>> cos( 2 * pi)
1.0
余弦函数工作正常,但我得到了奇怪的答案
正弦。这是一个错误吗?我做错了吗?
>来自交互式窗口中的帮助(数学):
描述
此模块始终可用。它提供了对C标准定义的
数学函数的访问。
所以你看到的是被暴露的C库的行为。 />
尝试sin(pi * 0.5)以查看与cos(pi)或cos(pi * 2)类似的行为。
sin (pi * 0.5)是我的预期,但我希望罪(pi)得到0。
Max Erickson写道:
" Chris" < ch ********* @ gmail.comwrote:
>>来自math import *
sin(0)
0.0
>> sin(pi)
1.2246063538223773e-016
>> sin(2 * pi)
-2.4492127076447545e-016
>> cos(0)
1.0
>> cos(pi)
-1.0
>> cos(2 * pi)
$
余弦函数工作正常,但是我得到了奇怪的答案
正弦。这是一个错误吗?难道我做错了什么?
来自交互式窗口中的帮助(数学):
描述
此模块始终可用。它提供了对C标准定义的
数学函数的访问。
所以你看到的是被暴露的C库的行为。 />
尝试sin(pi * 0.5)以查看与cos(pi)或cos(pi * 2)类似的行为。
>>from math import *
>>sin(0)
0.0
>>sin(pi)
1.2246063538223773e-016
>>sin(2*pi)
-2.4492127076447545e-016
>>cos(0)
1.0
>>cos(pi)
-1.0
>>cos(2*pi)
1.0
The cosine function works fine, but I''m getting weird answers for sine.
Is this a bug? Am I doing something wrong?
解决方案
Chris wrote:>from math import *
sin(0)
0.0
>sin(pi)
1.2246063538223773e-016
>sin(2*pi)
-2.4492127076447545e-016
>cos(0)
1.0
>cos(pi)
-1.0
>cos(2*pi)
1.0
The cosine function works fine, but I''m getting weird answers for sine.
Is this a bug? Am I doing something wrong?What answer do you suppose you get in version 2.4?
"Chris" <ch*********@gmail.comwrote:
>>>from math import *
sin(0)
0.0
>>>sin(pi)
1.2246063538223773e-016
>>>sin(2*pi)
-2.4492127076447545e-016
>>>cos(0)
1.0
>>>cos(pi)
-1.0
>>>cos(2*pi)
1.0
The cosine function works fine, but I''m getting weird answers for
sine. Is this a bug? Am I doing something wrong?
>From help(math) in an interactive window:
DESCRIPTION
This module is always available. It provides access to the
mathematical functions defined by the C standard.
So what you are seeing is the behavior of the C library being exposed.
Try sin(pi*0.5) to see similar behavior to cos(pi) or cos(pi*2).
sin(pi*0.5) is what I expected, but I expected to get 0 for sin(pi).
Max Erickson wrote:"Chris" <ch*********@gmail.comwrote:
>>from math import *
sin(0)0.0
>>sin(pi)1.2246063538223773e-016
>>sin(2*pi)-2.4492127076447545e-016
>>cos(0)1.0
>>cos(pi)-1.0
>>cos(2*pi)1.0
The cosine function works fine, but I''m getting weird answers for
sine. Is this a bug? Am I doing something wrong?
From help(math) in an interactive window:
DESCRIPTION
This module is always available. It provides access to the
mathematical functions defined by the C standard.
So what you are seeing is the behavior of the C library being exposed.
Try sin(pi*0.5) to see similar behavior to cos(pi) or cos(pi*2).
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