急,求不定积分In(x^2+1)dx ∫下面是0 上面是3

来源:学生作业帮助网 编辑:作业帮 时间:2024/08/03 13:34:07
急,求不定积分In(x^2+1)dx ∫下面是0 上面是3
xUooF*N Gs%4mTi/x1c6b뀢m֢Ilۛt|-N|qrx{~{]+쌮ܯod<ζV})=BR/WG?41N1TZV$ovZô)#~-grRk sdpd!^pSKVQDrXVgc:uNL_i84δ֭bvƏ83.go %E6_qd$ Wdm^I7,# ;X?w=b{Jy_~OP6L;6k64MdaSULHhX,K,֩i*n|TTy.ZX։mGС6*DA0YWn(gdp=;v<z<IsesD'oF=ϭ5/Px~B[)4)] UYCU@A$R|"jjBu f5pڷL ӭ|A6\^9 (VPHxtm d(^M<0"XO1;$ұ  cBg^KM$TG%6fHh*r_{BB~g b\Ku njO`S1uQ-7[Ϲrzq%T]?ޠ 43:7\kz^޷w{ٵç[-v<ǮYKD aן' 'lkK&׋avz,x2i R

急,求不定积分In(x^2+1)dx ∫下面是0 上面是3
急,求不定积分In(x^2+1)dx ∫下面是0 上面是3

急,求不定积分In(x^2+1)dx ∫下面是0 上面是3
∫(0,3)ln(x²+1)dx
=xln(x²+1)|(0,3)-∫(0,3)xdln(x²+1)
=3ln10-∫(0,3)2x²/(x²+1)dx
=3ln10-2∫(0,3)(x²+1-1)/(x²+1)dx
=3ln10-2∫(0,3)[1-1/(x²+1)]dx
=3ln10-2∫(0,3)dx+2∫(0,3)1/(x²+1)dx
=3ln10-6+2arctan3.

答案是:

然后你把3和0代进去相减,得3ln(10)-4+2arctan(3)。


不定积分的具体步骤:

Take the integral:
integral log(1+x^2) dx
For the integrand log(1+x^2), integrate by parts,  integral f dg = f g- integral g df, where 
f = log(1+x^2),     dg =   dx,
df = (2 x)/(1+x^2)  dx,     g = x:
= - integral (2 x^2)/(1+x^2) dx+x log(1+x^2)
Factor out constants:
= -2 integral x^2/(1+x^2) dx+x log(1+x^2)
For the integrand x^2/(1+x^2), do long division:
= -2 integral (1-1/(1+x^2)) dx+x log(1+x^2)
Integrate the sum term by term and factor out constants:
= -2 integral 1 dx+2 integral 1/(1+x^2) dx+x log(1+x^2)
The integral of 1/(1+x^2) is tan^(-1)(x):
= 2 tan^(-1)(x)-2 integral 1 dx+x log(1+x^2)
The integral of 1 is x:
= -2 x+2 tan^(-1)(x)+x log(1+x^2)+constant
Which is equal to:
Answer: |  
|  = 2 tan^(-1)(x)+x (-2+log(1+x^2))+constant


  1. 你给出了上下限,这是定积分。

  2. 那个符号是ln(小写L),不是In(不是大写i)。