Application of DerivativeMedium
Question
The length of a longest interval in which the function 3sin x - 4sin3 x increasing, is
Options
A.

B.

C.

D.π
Solution
Let f(x) = 3sin x - 4sin3 x = sin 3x
The longest interval in which sin x is increasing, is of length π.
So, the length of largrst interval in which
f(x) = sin 3x is increasing, is
The longest interval in which sin x is increasing, is of length π.
So, the length of largrst interval in which
f(x) = sin 3x is increasing, is
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