Do we need to convert the system of calculator to red in like this queation
Sorry I don't understand what you mean.
In the ( calculator ) there are many systyem for exampl when you press MODE button in calculator you can chose ( Deg ) or ( Rad ) or ( Gra )
my queation now do we need to change the system of calculator to rad in like above question
Yes, you do.
In any problem where you do not specifically have angles given in degrees, you should think of arguments of trig functions as being in radians.
(You had said "in red" before rather than "in rad"!)
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