why trigonometry input in degrees gives wrong results

Hello, Here is a simple trigonometry functions where i have given data in degrees and radians, why i am getting a wrong result when i am giving in degrees.

>> a=30 a =

    30
>> b=pi/6
b =
    0.5236
>> c=sin(a)
c =
   -0.9880
>> d=sin(b)
d =
    0.5000

Answer 1

[Azzi Abdelmalek]

If a is in degree you need to use another function

sind(3)

Also, when you say a is in degree, you know this, but how the function sin knows if it's degree or rad? the function sin consider a in radian.

Answer 2

[Image Analyst]

Use the "d" versions of the trig functions when you want to input in degrees:

sind(30) % Uses sind() rather than sin().
sin(pi/6)

ans = 0.5
ans = 0.5