How do you find the derivative of $ln(cosx)$ ?

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Answer 1 · 2015-10-09T18:26:30

Use the derivative of $ln$ and the chain rule.

$d/dx(lnu) = 1/u d/dx(u)$

So $d/dx(ln(cosx)) = 1/cosx d/dx(cosx)$ .

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How do you find the derivative of ln(cosx)ln(cosx)?