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The constant factor rule in integration is a dual of the constant factor rule in differentiation, and is a consequence of the linearity of integration. It states that a constant factor within an integrand can be separated from the integrand and instead multiplied by the integral. For example, where k is a constant: == Proof == Start by noticing that, from the definition of integration as the inverse process of differentiation: : Now multiply both sides by a constant ''k''. Since ''k'' is a constant it is not dependent on ''x'': : Take the constant factor rule in differentiation: : Integrate with respect to ''x'': : Now from (1) and (2) we have: : : Therefore: : Now make a new differentiable function: : Substitute in (3): : Now we can re-substitute ''y'' for something different from what it was originally: : So: : This is the constant factor rule in integration. A special case of this, with ''k''=-1, yields: : 抄文引用元・出典: フリー百科事典『 ウィキペディア(Wikipedia)』 ■ウィキペディアで「constant factor rule in integration」の詳細全文を読む スポンサード リンク
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