如何求解这个微积分题目?

如题所述

第1个回答  2023-12-02
2+sinx=2sin(x/2)^2+2cos(x/2)^2+2sin(x/2)cos(x/2)
dx/(2+sinx)=sec(x/2)^2dx/[2+2tan(x/2)^2+2tan(x/2)]
=d(tan(x/2))/[1+tan(x/2)+tan(x/2)^2]
令u=tan(x/2)
原积分=∫du/(1+u+u^2)
=∫d(u+1/2)/[3/4+(u+1/2)^2](用∫dx/(a^2+x^2)公式,取a=√3/2)
=1/a*arctan[(u+1/2)/a]+C
=2√3/3*arctan{[2√3tan(x/2)+√3]/3}+C
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