Help with IntegralS Very Important Quick

[Student from UA]

So the last is 10 =)
tell please what i must take for u and what for dv...

 

[Hootenanny]

So the last is 10 =)
tell please what i must take for u and what for dv...

Question 10 is just another application of the product rule. Let u=(1-3x) and dv=cos(2x)

bollocks and stuff

 

[VietDao29]

So the last is 10 =)
tell please what i must take for u and what for dv...

Post #67, and post #71 should answer that:
(1 - 3x) is an algebraic function, and cos(2x) is a trig function. The one that stands before the other in the sequence LIATE should be chosen for u, and the rest for dv. So what should be u, and dv this time?

 

[Student from UA]

$$\int cos2x dx$$ How to do?

 

[Student from UA]

LIATE -what is it? givee me link . i want read it.

 

[VietDao29]

$$\int cos2x dx$$ How to do?

You should let u = 2x.
When you have to deal with:
$$\int \sin(ax + b) dx$$
$$\int \cos(ax + b) dx$$
$$\int \tan(ax + b) dx$$
$$\int e ^ {ax + b} dx$$
$$\int \frac{1}{ax + b} dx$$
...
You should let u = ax + b
Or, in general, when deadling all the function f(ax + b), where $$\int f(x) dx$$ can be found easily, make the u-substitution u = ax + b.

LIATE -what is it? givee me link . i want read it.

It's right in the post #67. :)

 

[Student from UA]

Liate -good. I will write in my note... =) very interesting rule

 

[Student from UA]

U know.. I have done the 10th. It`s VICTORY! TAda! =)

 

[Student from UA]

Thx! Thx To All WHo help ME to do my Home Work! U`re a very good persons and Very very Clever. And I don`t know why a lot of XXXXX say that USA - And Americans are very ... O don`t think so... U are very friendly people and can help other people in any time. One more thx. If i would have some qustions in future, i imidiatly will go to this nice foorum to nice people =) Thx a lot.!

 

[cristo]

Well.. we're not all from the USA... in fact I don't think anyone who helped in this thread is!

Anyway, I'm glad you got your work done. Good luck in the future.

 

[Student from UA]

don`t mater where are u from! becouse u are super mens =) i`m very happy that i`m find u!

 

[BSMSMSTMSPHD]

That was one of the funniest threads I've ever read through.

 

[Hootenanny]

That was one of the funniest threads I've ever read through.

And why would you say that?

 

[BSMSMSTMSPHD]

It was like reading a really dramatic story that I didn't know the ending to. At times, I thought the poor guy wasn't going to get the answers he needed. But, he kept working hard, and eventually came through. Then he proclaimed VICTORY, and thanked the USA! It was straight out of Hollywood.

Usually I don't read through 100-post threads, but this was a next-clicker (page-turner).