NationStates Jolt Archive

im stuck at this integral where u=t

please help

http://i26.photobucket.com/albums/c144/slicknick727/integral.jpg

thanks

i know the integral of (du)/(u^2+1) equals arctan(u), i think that might have something to do with it

this is why I do biology.......

Yea, you can transform it into an arctg, just divide it by 1/9, I think (make it in my head) you will get arctg (1/3x) (where x is the variable)

Yea, you can transform it into an arctg, just divide it by 1/9, I think (make it in my head) you will get arctg (1/3x) (where x is the variable)


im sorry but i dont understand. so what i do is divide the inside :confused:

if you dont mind, i also need help with this one:
You've done the work already. All you do now is use the general form

[ uv - Integral( v du/dt) dt ]

And apply bounds between 4 and 1 to the whole equation.

There really isn't any specific trick to this one. v du/dt cancels neatly to (2/3)(x^1/2) so the second integral is a simple one. Perhaps it's just a simple algebra problem you're having?