求∫e∧3√xdx的不定积分

如题所述

第1个回答  2012-11-19
解:
令√x=t,则x=t^2,dx=2tdt
原积分
=∫(e^3t)2tdt
=(2/3)∫tde^(3t)
=(2/3)[te^(3t)-(1/3)∫e^(3t)d(3t)]
=(2/3)[te^(3t)-(1/3)∫de^(3t)]
=(2/3)[te^(3t)-(1/3)e^(3t)]
=(2/3)e^(3t)(t-1/3)
第2个回答  2012-11-19
令x=t²,dx=2tdt
∫(e^3√x)dx
=∫(e^3t)2tdt
=(2/3)∫tde^(3t)
=(2/3)[te^(3t)-∫e^(3t)dt]
=(2/3)[te^(3t)-(1/3)∫e^(3t)d(3t)]
=(2/3)[te^(3t)-(1/3)∫de^(3t)]
=(2/3)[te^(3t)-(1/3)e^(3t)]
=(2/3)e^(3t)(t-1/3)
=(2/3)e^(3√x)(√x-1/3)本回答被网友采纳
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