Calculating sin and cos functions

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Hello, i calculated the value of sin(45) in Matlab, the result was sin(45)=0.8509 and for cosin i got cos(45)= 0.5253. From general mathematics we know that sin(45)=cos(45) then why Matlab is giving different results??

采纳的回答

Paulo Silva
Paulo Silva 2011-5-29
Those functions work in radians not degrees, try this
cosd(45)
sind(45)
  3 个评论
Abdullah Amin
Abdullah Amin 2021-12-18
y=sin(-75) then y variable should carry value
+1 -1 +75 -75
Walter Roberson
Walter Roberson 2021-12-18
It is not clear to me why sin() of a scalar should result in a vector of length 4 ? Or why those particular values should be output ?

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更多回答(5 个)

bym
bym 2011-5-29
sin() & cos() arguments are in radians. If you want degrees use
sind() cosd()
  3 个评论
Muhammed Çelik
Muhammed Çelik 2020-4-20
or, you can do like this sin(degree*pi/180)
Steven Lord
Steven Lord 2020-4-20
If you're going to convert degrees to radians or vice versa, use the deg2rad or rad2deg functions moved from Mapping Toolbox to MATLAB in release R2015b rather than the "magic number" of pi/180.

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krishna sutradhar
krishna sutradhar 2021-6-23
编辑:Walter Roberson 2021-12-18
sin(2250 ) + cot(300 ) + tan-1 (1/2) + 10e-10 + 9x10-2 + (log1010)3 + (loge10)5
  2 个评论
Walter Roberson
Walter Roberson 2021-12-18
sind(2250) + cotd(300) + atand(1/2) + 10e-10 + 9*10^-2 + log10(10)^3 + log(10)^5
ans = 92.8037
Nishith Sarkar
Nishith Sarkar 2022-6-29
编辑:Nishith Sarkar 2022-6-29
Question: sin(225) + cot(30) + tan-1(1/2) + 10e-10 + 9x10-2 + (log1010)3 + (loge10)5
>> ns1=sind(225)
ns1 =
-0.7071
>> ns2=cotd(30)
ns2 =
1.7321
>> ns3=atand(1/2)
ns3 =
26.5651
>> ns4=10e-10
ns4 =
1.0000e-09
>> ns5=9*10^-2
ns5 =
0.0900
>> ns6=log10(10)^3
ns6 =
1
>> ns7=log(10)^5
ns7 =
64.7260
>> Nishith=ns1+ns2+ns3+ns4+ns5+ns6+ns7
Nishith =
93.4059

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Vishali Bansal
Vishali Bansal 2021-10-3
>> cos^-1(0.23)

Adedotun Taiwo
Adedotun Taiwo 2022-2-14
Cos(45)
  1 个评论
Walter Roberson
Walter Roberson 2022-2-14
MATLAB is case sensitive. That would not work.
Cos(45)
Unrecognized function or variable 'Cos'.
Paulo correctly answered a decade ago that if you are using degrees, use sind() and cosd()

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Nishith Sarkar
Nishith Sarkar 2022-6-29
编辑:Nishith Sarkar 2022-6-29
Answer please::
x=3cos50π+10sin300π-cos100π
  2 个评论
Walter Roberson
Walter Roberson 2022-6-29
编辑:Walter Roberson 2022-6-29
Pi = sym(pi);
x = 3*cos(50*Pi) + 10*sin(300*Pi) - cos(100*Pi)
x = 
2
Steven Lord
Steven Lord 2022-6-29
You don't need to use Symbolic Math Toolbox here. Use the sinpi and cospi functions instead.
x = (0:8).'/2;
s = sinpi(x);
c = cospi(x);
result = table(x, s, c)
result = 9×3 table
x s c ___ __ __ 0 0 1 0.5 1 0 1 0 -1 1.5 -1 0 2 0 1 2.5 1 0 3 0 -1 3.5 -1 0 4 0 1

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