Question

Найти производную функции
y=-3ctg x+cos3x

Answer 1

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Answer 2

$y'=(-3ctg x+cos3x)' =(-3ctg x)'+(cos3x)' = \\ \\ = -3 \frac{-1}{sin^2x} - 3sin3x = 3( \frac{1}{sin^2x} - sin3x)$