Write the set of values of `a` for which `f(x)=cosx+a^2\ x+b` is strictly increasing on `R` .

Explanation

`f(x)=cos x+a^{2} x+b`
`


f^{prime}(x)=-sin x+a^{2}`


for strictly increasing
`

f^{prime}(x)>0`
`
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