Let `f:{-pi/2,\ pi/2}->R` be a function defined by `f(x)=cos[x]dot` Write range `(f)` .

Explanation

`f:(-frac{pi}{2}, frac{pi}{2}) arrow R` defined by `f(x)=cos [x]`


Domain `=(frac{-pi}{2}, frac{pi}{2})`


As `pi=frac{22}{7}`


`Rightarrow` Domain `=(-1.57,1.57)`


`Rightarrow` So, `cos [{x}]=cos (-2)=cos 2`, for all `{x} in(-1.57,0)`


`Rightarrow` Also, `cos 0=1`, for `{x}=0`


`Rightarrow` And `cos [x]=cos 1`, for all `x in(0,1.57)`


`therefore` Range `={1, cos 1, cos 2}`