2x-1 x 2的不定积分-搜答案-百度作业网

∫[2x/(x^2+x+1)]dx=∫[(2x+1)/(x^2+x+1)]dx-∫dx/(x^2+x+1)=ln|x^2+x+1|-∫dx/(x^2+x+1)considerx^2+x+1=(x+1/

∫1/(x²-x-2)dx=∫1/[(x-2)(x+1)]dx=1/3∫[1/(x-2)-1/(x+1)]dx=1/3[∫1/(x-2)dx-∫1/(x+1)dx]=1/3[ln(x-2)-

∫(lnx-1)/x²dx=-∫(lnx-1)d(1/x)=-[(lnx-1)/x-∫1/xd(lnx-1)]=-(lnx-1)/x+∫1/x²dx=-(lnx-1)/x-1/x+

答：1.∫arcsinxdx可用分部积分原式=xarcsinx-∫x/√(1-x^2)dx=xarcsinx+√(1-x^2)+C2.∫e^(√x+1)dx换元,令√(x+1)=t,则x=t^2-1,

∫arctanxdx/[x^2(1+x^2)]=∫arctanxdx/x^2-∫arctanxdx/(1+x^2)=∫arctanxd(-1/x)-∫arctanxdarctanx=-(arctanx

1/(x+1)(x+2)(x+3)=1/(x+1)[1/(x+2)-1/(x+3)]=1/[(x+1)(x+2)]-1/[(x+1)(x+3)]=1/(x+1)-1/(x+2)-1/2[1/(x+1)

∫xlnx/(1+x^2)^2dx=1/2*∫lnx/(1+x^2)^2d(1+x^2)=-1/2*∫lnxd[1/(1+x^2)]=-1/2*lnx*1/(1+x^2)+1/2*∫[1/(1+x^2

令1/x=t则原式=∫arctant/(1+1/t²)*(-1/t²)dt=∫-arctant/(1+t²)dt=∫-arctantdarctant=-1/2arctan

配方：1＋x－x^2＝5/4－(x-1/2)^2,套用不定积分公式（∫dx/√(a^2-x^2)）结果是arcsin((2x-1)/√5)＋C

令x=tant,t∈(-π/2,π/2),则√(1+x²)=sect,dx=sec²tdt∫√(1+x²)dx=∫sec³tdt=∫sectd(tant)=se

令x=siny原式=∫1/(sinycosy)*cosydy=∫1/[2cos^2(y/2)]/tan(y/2)dy=∫d(tany/2)/tan(y/2)=ln|tan(y/2)|+C=ln|(1-

∫dx/(x^2+x)=∫[1/x-1/(x+1)]dx=ln|x/(x+1)|+C

1/(1+x^2)d(1+x^2)=ln(1+x^2)+C

∫x/(x^2＋x＋1)dx=(1/2)∫dln(x^2+x+1)-(1/2)∫1/(x^2＋x＋1)dx=(1/2)ln(x^2+x+1)-(1/2)∫1/(x^2＋x＋1)dxx^2＋x＋1=(x

∫［（x－1）/（x^2＋3）］dx＝∫［x/（x^2＋3）］dx－∫［1/（x^2＋3）］dx＝（1/2）∫［1/（x^2＋3）］d（x^2＋3）－（1/√3）∫｛1/［（x/√3）^2＋1］｝d（

再答：诚邀您加入百度知道团队“驾驭世界的数学”。

分部积分法再答：

(-(x/(1+x^2))+ArcTan[x])/2