# Cos 2x cosx

Input |
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cos(2 x) cos(x) |

Series expansion at x=0 |

1 – (5 x^2)/2 + (41 x^4)/24 + O(x^6) (Taylor series) |

Derivative |

d/dx(cos(2 x) cos(x)) = 1/2 (-sin(x) – 3 sin(3 x)) |

Indefinite integral |

integral cos(x) cos(2 x) dx = 1/6 (3 sin(x) + sin(3 x)) + constant |