Calculating sin and cos functions

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Mohsin Shah 2011-5-29

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评论： Walter Roberson 2021-12-18

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??

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Paulo Silva 2011-5-29

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Those functions work in radians not degrees, try this

cosd(45)
sind(45)

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Abdullah Amin 2021-12-18

y=sin(-75) then y variable should carry value

+1 -1 +75 -75

Walter Roberson 2021-12-18

@Abdullah Amin

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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bym 2011-5-29

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sin() & cos() arguments are in radians. If you want degrees use

sind() cosd()

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Muhammed Çelik 2020-4-20

or, you can do like this sin(degree*pi/180)

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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