So 1 = (180/π).
So 0
On [0, π/2], f(x)=sinx is increasing function.
So here we are 1
f( 1)& lt; f(π)& lt; f(( 180/π))
Namely sin1< sinπ <; sin 1
(Note: You said π, not π)
Because π/4
So cos 1