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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