∫xcosx sin^3x

x^2/[(x-3)(x+2)^2=(9/25)[1/(x-3)]+(16/25)[1/(x+2)]-(20/25)[1/(x+2)^2].原式=(9/25)∫1/(x-3)dx+(16/25)∫1/

答案见附图

∫√x/(√x-3^√x)dx换元,x=t^6=∫t^3/(t^3-t^2)d(t^6)=∫t^3(6t^5)/(t^3-t^2)dt=6∫t^6/(t-1)dt=6∫(t^6-1+1)/(t-1)d

(x^2-x+6)/(x^3+3x)=2/x-(x+1)/(x^2+3).原式=∫2/xdx-∫(x+1)/(x^2+3)dx=2ln|x|-(1/2)ln(x^2+3)-(1/√3)arctan(x

把下边有理化,就非常容易了.再问：求详细再答：等下，我回自习室给你写下啊再答：再答：再答：再答：答案是不是它再答：应该是把3换成2是平方我看错了再问：书上的参考答案是ln[(x+3)/(x+2)]&#

原式=∫[2/x-2/(x+1)-2/(x+1)²+1/(x+1)³]dx=2ln│x│-2ln│x+1│+2/(x+1)-(1/2)/(x+1)²+C(C是积分常数)=

设x+3＝t→dx＝dt,代入原式得∫[(2x²+3x-5)/(x+3)]dx＝∫[(2(t-3)²+3(t-3)-5)/t]dt＝∫[2t+(4/t)-9]dt＝t²+

当x=0时,f(x)不连续,故f(x)的原函数分成两部分：x>0,∫f(x)dx=∫x㏑(1+x^2)dx=(1/2)∫㏑(1+x^2)d(x^2)=(1/2)ln|ln(1+x^2)|+C1x

∫(x²+7x+12)/(x+3)dx=∫(x+3)(x+4)/(x+3)dx=∫(x+4)dx=x平方/2+4

[f(x)/f'(x)]'=[f'²(x)-f(x)f''(x)]/f'²(x)=1-f(x)f''(x)/f'²(x)因此题目中的被积函数为：[f(x)/f'(x)-f

原式∫[(3e)^x-e^(2x)]dx=∫(3e)^xdx-∫e^(2x)dx=(1/ln(3e)∫ln(3e)*(3e)^xdx-1/2∫e^(2x)d(2x)=(3e)^x/ln(3e)-e^(

(1+x³)/[x(1-x³)]=(1+x³)/[x(1-x)(1+x+x²)]令(1+x³)/[x(1-x)(1+x+x²)]=A/(1+

∫2^x*3^x/(9^x-4^x)dx=∫(2/3)^xdx/[1-(4/9)^x]=[ln(2/3)]^(-1)∫d[(2/3)^x]/{1-[(2/3)^x]^2}={[ln(2/3)]^(-1

每一个分出来积分,答案是2x^2-2x^(3/2)-5lnx

∫x/（x^2+3x+3）dx=∫(x+3/2-3/2)/（x^2+3x+3）dx=∫(x+3/2)/（x^2+3x+3）dx-3/2∫dx/（x^2+3x+3)=1/2∫d(x^2+3x+3)/（x

4/3*x^4+3/2x^2+1/4*x^2+c再问：可我算得x^4/4+(3/2)x^2+2lnlxl+c再答：你的对，我看错了

[(x^3-2x^2+x+1)/(x^4+5x^2+4)]=1/(x^2+1)+(x-3)/(x^2+4).原式=∫1/(x^2+1)dx+∫(x-3)/(x^2+4)dx=arctanx+(1/2)

∫(x^2-3x)/(x+1)dx=∫[(x+1)(x-4)/(x+1)+4/(x+1)]dx=∫(x-4)dx+∫4/(x+1)dx=x²/2-4x+4ln(x+1)+C其中C为任意常数

原式=∫(3x^4+3x^2-2x^2-2+2)/(x^2+1)dx=∫[3x^2-2+2/(x^2+1)]dx=x^3-2x+2arctanx+C