Q6 of 96 Page 17

Find the vales of ‘a’ for which the function f(x) = sinx – ax + 4 is increasing function on R.

f(x) = Sin x – ax + 4


f’(x) = Cos x – a + 0


f’(x) = Cos x – a


f(x) is increasing on R.


f’(x) > 0


Cos x – a > 0


Cos x > a


Cos x ≥ -1, ∀x ϵ R


a < -1


a ϵ (-∞, -1)


Hence the required set of values is a ϵ (-∞, -1).


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