Find `(dy)/(dx)`, when: `y=cosxcos2x cos3x`

1.	Find `(dy)/(dx)`, when: `y=cosxcos2x cos3x`
Answer» Correct Answer - `-(cosx cos2x cos3x).[tanx+2 tan 2x+3 tan 3x]` `logy=log cosx+logcos2x+log cos3x` `rArr(1)/(y).(dy)/(dx)=(-sinx)/(cosx)-(2sin2x)/(cos2x)-(3sin3x)/(cos3x)` `rArr(dy)/(dx)=y.{-tanx-2 tan2x-3 tan 3x}.`

Discussion

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