- anonymous

Integrate this pls

- jamiebookeater

See more answers at brainly.com

At vero eos et accusamus et iusto odio dignissimos ducimus qui blanditiis praesentium voluptatum deleniti atque corrupti quos dolores et quas molestias excepturi sint occaecati cupiditate non provident, similique sunt in culpa qui officia deserunt mollitia animi, id est laborum et dolorum fuga.
Et harum quidem rerum facilis est et expedita distinctio. Nam libero tempore, cum soluta nobis est eligendi optio cumque nihil impedit quo minus id quod maxime placeat facere possimus, omnis voluptas assumenda est, omnis dolor repellendus.
Itaque earum rerum hic tenetur a sapiente delectus, ut aut reiciendis voluptatibus maiores alias consequatur aut perferendis doloribus asperiores repellat.

Get this expert

answer on brainly

SEE EXPERT ANSWER

Get your **free** account and access **expert** answers to this

and **thousands** of other questions

- freckles

integration!!!!!

- freckles

looks like we going to need some completing the square and some trig sub action

- welshfella

yes

Looking for something else?

Not the answer you are looking for? Search for more explanations.

## More answers

- freckles

\[as^2+bs+c \\ a(s^2+\frac{b}{a}s)+c \\ a(s^2+\frac{b}{a}s+(\frac{b}{2a})^2)+c-a(\frac{b}{2a})^2 \\ a(s+\frac{b}{2a})^2+c-\frac{ab^2}{4a^2} \\ a(s+\frac{b}{2a})^2+c-\frac{b^2}{4a} \\ a(s+\frac{b}{2a})^2+\frac{4ac-b^2}{4a}\]

- freckles

that is generally how I complete the square

- freckles

if you want you can use that as a formula too

- freckles

you know of course assuming a isn't 0

- SolomonZelman

\(\large\color{slate}{\displaystyle\int\limits_{0}^{2000}\frac{1}{12s+0.025^2}~ds}\) it is like this?!

- SolomonZelman

or what is exactly the integral?

- freckles

there is a square root over the bottom part

- anonymous

Yes @SolomonZelman

- freckles

oh no square root?

- anonymous

Trying to find the value of s

- freckles

wait that 5 is a s?

- freckles

I'm no confused

- SolomonZelman

\(\large\color{slate}{\displaystyle\int\limits_{0}^{2000}\frac{1}{\sqrt{12s+0.025}^2}~ds}\) ???
I am also confused

- anonymous

that's s

- SolomonZelman

the last thing I wrote

- SolomonZelman

?

- SolomonZelman

so square root is raised to the second power?

- freckles

I thought it was:
\[\int\limits_{0}^{2000}\frac{ds}{\sqrt{12s+0.02s^2}}\]

- SolomonZelman

is that 5 or s at the end of the root?

- SolomonZelman

can you draw it pliz? sliver x?

- anonymous

@freckles was right. It isnt 5..

- SolomonZelman

\(\large\color{slate}{\displaystyle\int\limits_{0}^{2000}\frac{1}{\sqrt{12s+0.02s^2}}~ds}\)

- anonymous

yes yes

- SolomonZelman

I ended up with partial fractions which are solvable, but it took too many steps, I think it is not correct to post it here.

- freckles

you show eventually wind up with
this (if you do the completing the square and you aim for a trig sub)
\[\frac{1}{30 \sqrt{2}}\int\limits_{0}^{2000} \frac{ds}{\sqrt{(\frac{s+300}{300})^2-1} }\]

- freckles

should (not show)

- freckles

\[\sec^2(\theta)-1=\tan^2(\theta) \\ \text{ so } \sec(\theta)=\frac{s+300}{300} \\ \]

- anonymous

so its sec^2 theta

- SolomonZelman

this is what I ended up after I have written all possible latex :o-:()

- SolomonZelman

I completed the square in the root, and factored out of 1/ âˆš(0.02)
then I did u=s+300

- SolomonZelman

then partial fractions decomposition/expansion

- SolomonZelman

\(\large\color{slate}{\displaystyle\frac{\sqrt{2}}{120} \int\limits_{30}^{2300}\frac{\sqrt{u^2-90,000}}{u-300}-\frac{\sqrt{u^2-90,000}}{u+300}~du}\)

- SolomonZelman

(also factored out of 600)

- SolomonZelman

won't disturb tho'

- anonymous

And I know its a long long process..

- SolomonZelman

I hate bad integrals like yours....

- SolomonZelman

I would use geom. shapes if it was my choice.
To many equations, sick of them:o-:(

- anonymous

Well actually this was derived in a dynamics problem. :(

- SolomonZelman

oh

- SolomonZelman

if you sure u derived it correctly.... (don't think you would make a mistake on that... i have seen you solve DE)

- freckles

I'm not really sure if you need anymore help me but let me know

- freckles

also @SolomonZelman your way is equivalent
but I think it still needs trig sub

- anonymous

@freckles after noted that it was sectheta.. whats next?

- freckles

differentiate

- SolomonZelman

perhaps, I was thinking of separating them into two integrals and in one go w=u-300
and in other p=u+300

- freckles

\[\frac{1}{30 \sqrt{2}}\int\limits_{0}^{2000} \frac{ds}{\sqrt{(\frac{s+300}{300})^2-1} }
\]
\[\sec(\theta)=\frac{s+300}{300} \\ \sec(\theta) \tan(\theta) d \theta=\frac{1}{300} ds \\ 300 \sec(\theta) \tan(\theta) d \theta =ds\]

- freckles

\[\frac{10}{\sqrt{2}} \int\limits_0^{arcsec(\frac{23}{3})} \sec(\theta) d \theta \]

- anonymous

okay @freckles im following =)

- SolomonZelman

((( When I did those in my class I had a nice math professor who would let use simpson's trapezoidal and midpoint rules, but on a condition that we find the max possible error, and use a bigger n. )))
not a fan of these:) bye

- freckles

should finally get:
\[\frac{10}{\sqrt{2}} \ln|\frac{23}{3}+\frac{1}{3} \sqrt{23^2-3^2}|-\frac{10}{\sqrt{2}}\ln|1+0|\]

- anonymous

lol @SolomonZelman thank you so much =)

- freckles

the second term is just 0

- freckles

\[\frac{10}{\sqrt{2}} \ln|\frac{23}{3}+\frac{2 \sqrt{130}}{3}|\]

- freckles

I will let you play with that and dress it however you want

- anonymous

Got 17.78

- SolomonZelman

didn't do much.. yw

- freckles

by the way you can drop the | |

- SolomonZelman

close

- SolomonZelman

wolfram gives 19.274

- anonymous

Ops. Its 22.004

- freckles

yeah you are a little bit off
by the way since this was an ugly beast
and you probably will come up again a lot more ugly foe
I suggest wolfram for checking your answers

- freckles

oops and solomon already said something about wolfram

- freckles

http://www.wolframalpha.com/input/?i=10%2Fsqrt%282%29*ln%7C23%2F3%2B2%28sqrt%28130%29%2F3%29%7C

- freckles

which you could also put the initial integral in there
and compare what I got with that
should be same thing

- freckles

http://www.wolframalpha.com/input/?i=integrate%281%2Fsqrt%280.02s%5E2%2B12s%29%2Cs%3D0..2000%29
they actually round theirs to the nearest thousandth and don't off any more digits

- anonymous

Aaah yes yes..

- anonymous

Its 19..

- anonymous

Thank you so much @freckles

- anonymous

I still need to digest this..

- freckles

if you want to be exact
the answer is:
\[\frac{10}{\sqrt{2}} \ln(\frac{23+2 \sqrt{130}}{3}) \\ \text{ or if you just want to give a better answer than wolfram then you can say something like } \\ 19.273952\]

- anonymous

Thank you so much =)

- freckles

np

- anonymous

@freckles I wanna ask something.. Why did you use the completing the square?

- freckles

I did the completing the square
to do the trig sub
that usually works for things in this form:
\[\int\limits_{}^{}\frac{1}{\sqrt{(ax^2+bx+c)^n}}dx\]

- anonymous

Oh yes thank you!

- anonymous

@freckles how did you get the 300?

- anonymous

and also the 1/30 sqrt of 2?

- freckles

I followed what I said about completing the square:
\[as^2+bs+c \\ a(s^2+\frac{b}{a}s)+c \\ a(s^2+\frac{b}{a}s+(\frac{b}{2a})^2)+c-a(\frac{b}{2a})^2 \\ a(s+\frac{b}{2a})^2+c-\frac{ab^2}{4a^2} \\ a(s+\frac{b}{2a})^2+c-\frac{b^2}{4a} \\ a(s+\frac{b}{2a})^2+\frac{4ac-b^2}{4a}\]
You can use this as a formula but I will go through the steps with the numbers instead just for another example of how to complete the square:
\[0.02s^2+12s+0 \\ 0.02s^2+12s\\0.02(s^2+\frac{12}{0.02}s) \\ 0.02(s^2+\frac{12}{0.02}s+(\frac{12}{2(0.02)})^2)-0.02(\frac{12}{2(0.02)})^2 \\ 0.02(s+\frac{12}{2(0.02)})^2-0.02 \frac{12^2}{2^2(0.02^2)} \\ 0.02(s+\frac{12}{2} \frac{1}{0.02})^2-0.02 \frac{(2 \cdot 6)^2}{2^2(0.02)^2} \\ 0.02(s+6 \frac{1}{0.02})^2-0.02 \frac{2^2 6^2}{2^2(0.02)^2} \\ 0.02(s+6 \frac{100}{2})^2-0.02 \frac{ \cancel{2^2}6^2}{\cancel{2^2}(0.02)^2} \\ 0.02(s+3(100))^2-\cancel{0.02} \frac{6^2}{0.02^{\cancel{2}}} \\ 0.02(s+300)^2-\frac{36}{0.02} \\ 0.02(s+300)^2-\frac{3600}{2} \\ 0.02(s+300)^2-1800 \\ \frac{2}{100}(s+300)^2-1800 \\ 1800( \frac{2}{100(1800)}(s+300)^2-1) \\ 1800(\frac{2}{(100)18(100)}(s+300)^2-1) \\ 1800(\frac{2}{18(100)^2}(s+300)^2-1) \\ 1800(\frac{1}{9(100)^2}(s+300)^2-1) \\ \\ 1800(\frac{1}{(300)^2}(s+300)^2-1) \\ 1800((\frac{s+300}{300})^2-1)\]

- freckles

\[\sqrt{1800}=\sqrt{900 \cdot 2}=\sqrt{900} \sqrt{2} =30 \sqrt{2}\]

- freckles

is how I came to:
\[\frac{1}{30 \sqrt{2}}\int\limits_{0}^{2000} \frac{1}{\sqrt{(\frac{s+300}{300})^2-1}} ds\]

- anonymous

Thank you thank you soo much

- anonymous

@freckles how did you get the upper limit (arc sec 23/3)? =)

- freckles

s=2000 and \[\sec(\theta)=\frac{s+300}{300}\] plug in old limit into sub to find new limit

- anonymous

Ahh thank you so much @freckles =)

Looking for something else?

Not the answer you are looking for? Search for more explanations.