Re: Calculus (Substitution)...
[Prev][Next][Index][Thread]
Re: Calculus (Substitution)...
At 10:17 PM 11/12/98 -0600, Bill Risher wrote:
>At 09:48 PM 11/12/98 -0500, Thomas J. Hruska wrote:
>>Help! I have an integral that I can't work either forward or backward.
>>
>>Here is the problem (S = integral sign):
>>
>>S (e^x - 3)^(1/2) dx
>>
>>
>>The problem states that I have to use substitution, so:
>>
>>u = e^x - 3
>>du = e^x dx
>>du / (e^x) = dx
>>du / (u + 3) = dx
>>
>>S [u^(1/2) / (u + 3)] du
>>
>>That is as far as I have gotten. If someone could please help me finish
>>this problem I would be very grateful. My dad's own calculus books don't
>>help with this problem either. TIA
>
>I cant help with the process, but I can give you an answer to work towards:
>
>2*sqrt(e^x-3)-2*sqrt(3)*atan(sqrt(3*(e^x-3))/3)
>
>thats what my TI-89 says the answer is (you can add +C to the end if you
>want this as an anti-derivative)
As I said, I can't work it either forward or backword. I have the answer
in the back of my book (which is the same as what your 89 gave you), but I
still want to either derive it from the answer or take the integral. I'll
take the process either way. I don't care as long as I get it.
Thomas J. Hruska -- thruska@tir.com
Shining Light Productions -- "Meeting the needs of fellow programmers"
http://www.geocities.com/SiliconValley/Heights/8504
http://shinelight.home.ml.org
References: