Complex number and degrees
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Hi,
result of code
x=3*cos(pi)+3*sin(pi)*i
is -3.0000 0.0000i.
But result of this code
x=3*cosd(180)+3*sind(180)*i
is -3.
Why result of second code is not in form -3.0000 0.0000i.???
How can I do this without transformation from deg to rad???
Thank you
x=3*cos(pi)+3*sin(pi)*
1 个评论
Matt Kindig
2013-2-18
编辑:Matt Kindig
2013-2-18
In short, numerical precision. In the first case, MATLAB represents sin(pi) as 3.6739e-16 (on my x64 machine), while in the second case, sind(180) is identically zero. Both are equivalent.
采纳的回答
Azzi Abdelmalek
2013-2-18
编辑:Azzi Abdelmalek
2013-2-18
Because of precision problem with pi
sin(pi)=1.2246e-16
and
sind(180)=0
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Youssef Khmou
2013-2-18
编辑:Youssef Khmou
2013-2-18
hi Jhon,
i can not say why using cosd and sind gives only double not complex, but you can use exponential representation which is commonly used in Elec,Eng :
R= Magnitude * exp(j* Angle ) in radian
r=3*exp(j*pi)
另请参阅
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