ˆ   2    
¦   x    
¦ ———————— dx
¦       4  
  1 + x

how do you do this one???? i am up to here...

Quote:

下面是引用o_ice_o于2004-08-10 11:27 AM发表的 :
ˆ      
¦ 2 x    
¦ ———————— dx
¦       　４
‰ 1 + x
.......

then sub this back into, and u'll get 2x^2/(1+x^4)

how do you do this...?

2             2        
(x + ‹2x + 1)·(x - ‹2x + 1)

Quote:

下面是引用deportivo于2004-08-10 10:44 AM发表的 :
有答案么？看看结果对不对

check ur message plz

Quote:

下面是引用看烟花的猪于2004-08-10 1:26 PM发表的 :
答案还是tan(x)??

kidding me....

Quote:

下面是引用薄薄没香于2004-08-11 11:49 AM发表的 :
你们还没解出来?
看来高数还真不简单

i've got two answers now...and i've sent them to deportivo..forget to back up

Quote:

下面是引用galilette于2004-08-11 3:18 PM发表的 :
x^4+1=(x^2+sqrt(2)x+1)*(x^2-sqrt(2)x+1)
会这个分解就可以做了

yeah.. i'm up to here. but what next step?
it doesn't make any sense to me to get log from even by using
a/(x^2+sqrt(2)x+1)+b(x^2-sqrt(2)x+1)=1

...by using Derive 5