[ 3 / biz / cgl / ck / diy / fa / ic / jp / lit / sci / vr / vt ] [ index / top / reports ] [ become a patron ] [ status ]
2023-11: Warosu is now out of extended maintenance.

/sci/ - Science & Math

View post   
File: 10 KB, 429x410, 1304744390659.png [View same] [iqdb] [saucenao] [google]
3074808 No.3074808 [Reply] [Original]

So I have a question about the limits of integration for definite integrals.

I remember in calculus I that there are two methods by which you may deal with the bounds of integration when dealing with u-substitution.

One method was to actually input the bounds into your u-substitution and this would reevaluate the bounds.

The other method did not alter the bounds at all but it had something to do with not doing the substitution until later (or something).

Can anyone explain or remember what I am referring to?

>> No.3074866

No one remembers or were you all just taught one method?

>> No.3075053

I am confus.

What do you want explained?

>> No.3075076

I'm asking for the other method of dealing with the bounds of integration during u-substitution on definite integrals.

>> No.3075094

I think I know what you are talking about OP. Let me crack open my calc book.

>> No.3075121

>>3075094

Shit, I couldn't find it, and it's been forever since I've done a u-sub. I vaguely remember something about yeah, doing the integral and then subing in the changed bounds at the end or whatnot.

>> No.3075129

You would substitute in u as normal, but leave the limits as are. Then when you get the integral, you would replace u with x.

Right?

>> No.3075149

>>3075129

This. you just back-substitute x for u and leave the bounds as is (usually how I do it, but I don't actually write out my expression in terms of u)

is it really that difficult for you to figure that out yourself though?

>> No.3075268

That's exactly it! Thanks very much.

>> No.3075279

>>3075149

I don't really get to do definite integrals often. Every time I remember how I do them using 'back substitution', I wind up on some other subject that doesn't use definite..