definite integral

[rachaelmaria7]

Hello. I have a few of these out of about 48 of these type of probelms I need help with. I have been working on these for about 2 weeks now and came here as a last resort for help. If anyone has some time and and is willing to help me and walk me thru them I would really appreciate it. I know there are quite a few, if you cant help with all that is all right. Maybe I will figure some out in the mean time. Thank you!

Evaluate the definite integral.

1)

2)

3)

4)

5)

6)

7)

8)

9)

10)

11)

 

[happy]

In the rules of this forum, it says not to post a list of problems without showing any work. In two weeks of working on them, do you really have nothing to show? They're pretty basic. You should talk to your professor if you aren't able to figure them out in two weeks.

 

[tkhunny]

We can just skip the "indefinite" integrals?

 

[rachaelmaria7]

sorry some people are just not good at math, and I am one. I did ask my teacher and he said to figure it out myself. I have done the ones I can, but these I am stuck on. So I just said if anyone had some time and was willing to help me I would appreciate it. Hey if you want me to pay you I will, I am just trying to graduate and this is the only class i need for my BA.

 

[stapel]

If you're asking that the tutors "just give me the answers so I can pass", this is unlikely to generate helpful replies, I'm afraid.

Please understand that we cannot teach courses here. If after two weeks of effort, you have made absolutely no progress on any of these, then you need to have a talk with your instructor, as there is likely little we can do. For instance, I would have provided the following responses to get you started:

1) Use u-substitution on the denominator. If u = y - 9, so du = dy, then what do you get?

2) Use u-sub on the exponent.

3) There is no integral here...?

4) Is that "to the seventh power" on the "x" or on the log?

5) U-sub on the denominator looks useful.

6) Just use the regular "power" rule for integrals. It was probably the first (and easiest) rule they covered.

7) Same as (6).

8) Simplify to get t² - t^-2. Apply the Power Rule.

9) Try u-sub on the exponent.

10) Try u-sub on the argument of the cube.

11) Try u-sub on the denominator.

Did that help at all? If not, then I'm afraid there is likely little we can do.

There are places that will take your money and do your homework for you, if that's all you're looking for, by the way. This just isn't one of them. I apologize for any confusion.

Eliz.

 

[rachaelmaria7]

i dont want someone to give me the answers, i want someone to help me so i can find them by myself. i already spoke to my instructor and he told me he couldnt help me and to get online help. there are about 10 other students in my class struggling with these. like i said i came here as a last result.

 

[pka]

Try to understand these examples. Then apply the same to others.
\(\displaystyle \L
\begin{array}{l}
\int {\frac{{6x}}{{\left( {x + 2} \right)^5 }}dx,\quad u = x + 2\;\& \;du = dx\quad \Rightarrow \quad \int {\frac{{6\left( {u - 2} \right)}}{{u^5 }}du = \int {6u^{ - 4} - 12} } } u^{ - 5} du \\
\int\limits_1^2 {\frac{{t^8 - t^4 }}{{t^6 }}dt} = \int\limits_1^2 {\left( {t^2 - t^{ - 2} } \right)dt} \\
\int\limits_0^1 {\frac{{4x^3 }}{{\left( {1 + x^4 } \right)^6 }}dx} = \int\limits_1^2 {\frac{1}{{u^6 }}du} \\
\end{array}\)

 

[rachaelmaria7]

Try to understand these examples. Then apply the same to others.
\(\displaystyle \L
\begin{array}{l}
\int {\frac{{6x}}{{\left( {x + 2} \right)^5 }}dx,\quad u = x + 2\;\& \;du = dx\quad \Rightarrow \quad \int {\frac{{6\left( {u - 2} \right)}}{{u^5 }}du = \int {6u^{ - 4} - 12} } } u^{ - 5} du \\
\int\limits_1^2 {\frac{{t^8 - t^4 }}{{t^6 }}dt} = \int\limits_1^2 {\left( {t^2 - t^{ - 2} } \right)dt} \\
\int\limits_0^1 {\frac{{4x^3 }}{{\left( {1 + x^4 } \right)^6 }}dx} = \int\limits_1^2 {\frac{1}{{u^6 }}du} \\
\end{array}\)

the second one is 11/6 and the last one is -60 right?

 

[rachaelmaria7]

I did # 7 like this and got 2.67. Is that right?

 

[tkhunny]

I did # 7 like this and got 2.67. Is that right?

Maybe. It depends on how you managed that value. Too bad you aren't showing us your work or we could have a better opinion.

Some people are just not good at math, and I am one.

What's the point of trying to help you, then? If you can't do it, why bother? Let's lose the self-fulfilling attitude and learn some mathematics.

Did your teacher never demonstrate basic techniques? Something is wrong there.