The Total solution for NCERT class 6-12
Show that f(x) =sin x is an increasing function on (–π/2, π/2).
Given f (x) = sin x
⇒
⇒ f’(x)= cos x
Now, as given x ∈ (–π/2,π/2).
That is 4th quadrant, where
⇒ Cosx> 0
⇒ f’(x)> 0
Hence, condition for f(x) to be increasing
Thus f(x) is increasing on interval (–π/2, π/2).
