Find , when
y = sin x sin 2x sin 3x sin 4x
Let y = sin x sin 2x sin 3x sin 4x
Take log both sides:
⇒ log y = log (sin x sin 2x sin 3x sin 4x)
⇒ log y = log (sin x ) + log (sin 2x) + log (sin 3x) + log (sin 4x)
Differentiating with respect to x: