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QRAwarrior
Group Title
Evaluate the definite integral from u = 0 to u = 4 of:
\sqrt{1 + u^2}
dx
As you may have noticed, I have already done Usub.
 2 years ago
 2 years ago
QRAwarrior Group Title
Evaluate the definite integral from u = 0 to u = 4 of: \sqrt{1 + u^2} dx As you may have noticed, I have already done Usub.
 2 years ago
 2 years ago

This Question is Closed

Mimi_x3 Group TitleBest ResponseYou've already chosen the best response.0
Then where do you needhelp with?
 2 years ago

QRAwarrior Group TitleBest ResponseYou've already chosen the best response.0
Evaluating
 2 years ago

QRAwarrior Group TitleBest ResponseYou've already chosen the best response.0
Where do you people get your bike avatars from?
 2 years ago

QRAwarrior Group TitleBest ResponseYou've already chosen the best response.0
I do not want "Google" as an answer... :O
 2 years ago

lgbasallote Group TitleBest ResponseYou've already chosen the best response.0
looks trig sub...have you learned that yet?
 2 years ago

lgbasallote Group TitleBest ResponseYou've already chosen the best response.0
but we really did gust google this! i swear! :(
 2 years ago

Mimi_x3 Group TitleBest ResponseYou've already chosen the best response.0
What's the whole question?
 2 years ago

lgbasallote Group TitleBest ResponseYou've already chosen the best response.0
dw:1337521244254:dw
 2 years ago

QRAwarrior Group TitleBest ResponseYou've already chosen the best response.0
dw:1337521266266:dw
 2 years ago

QRAwarrior Group TitleBest ResponseYou've already chosen the best response.0
Yes I know that trig sub.
 2 years ago

lgbasallote Group TitleBest ResponseYou've already chosen the best response.0
dw:1337521291094:dw
 2 years ago

QRAwarrior Group TitleBest ResponseYou've already chosen the best response.0
But ultimately, you have to put a 4 into a trigonometric function's argument. How will that work?
 2 years ago

Mimi_x3 Group TitleBest ResponseYou've already chosen the best response.0
the problem is subbing in the limits???
 2 years ago

LagrangeSon678 Group TitleBest ResponseYou've already chosen the best response.1
convert the limits when using the trig sub
 2 years ago

lgbasallote Group TitleBest ResponseYou've already chosen the best response.0
dont forget to change back to x before evaluating
 2 years ago

Mimi_x3 Group TitleBest ResponseYou've already chosen the best response.0
No, you don't need to convert back
 2 years ago

lgbasallote Group TitleBest ResponseYou've already chosen the best response.0
otherwise you'll have to convert the limits in terms of theta
 2 years ago

QRAwarrior Group TitleBest ResponseYou've already chosen the best response.0
Ok let me see what happens:  tan(θ) = u/1  sec(θ) = \sqrt{1 + u^2} Then, sec^2(θ)dθ = du
 2 years ago

lgbasallote Group TitleBest ResponseYou've already chosen the best response.0
yep.. \[\int \sec^3 \theta d\theta\]
 2 years ago

QRAwarrior Group TitleBest ResponseYou've already chosen the best response.0
Then what is limits of integration wrt θ?
 2 years ago

QRAwarrior Group TitleBest ResponseYou've already chosen the best response.0
What is arctan(4)?
 2 years ago

QRAwarrior Group TitleBest ResponseYou've already chosen the best response.0
How did you get that?
 2 years ago

QRAwarrior Group TitleBest ResponseYou've already chosen the best response.0
I got sec^3(θ)
 2 years ago

lgbasallote Group TitleBest ResponseYou've already chosen the best response.0
it was sec^3 theta...ohh woops
 2 years ago

lgbasallote Group TitleBest ResponseYou've already chosen the best response.0
sec^3 theta = (sec^2 theta)sec theta (1+ tan^2 theta) sec theta \[\int \sec \theta + \tan^2 \theta \sec \theta\] lol got me stuck now
 2 years ago

QRAwarrior Group TitleBest ResponseYou've already chosen the best response.0
dw:1337523905957:dw @LagrangeSon678 @shivam_bhalla
 2 years ago

QRAwarrior Group TitleBest ResponseYou've already chosen the best response.0
@experimentX
 2 years ago

experimentX Group TitleBest ResponseYou've already chosen the best response.1
evaluate it individually .. \[ \int \sec \theta d\theta = \ln \sec\theta + \tan\theta\]
 2 years ago

experimentX Group TitleBest ResponseYou've already chosen the best response.1
this is a lot better http://answers.yahoo.com/question/index?qid=20110524035942AAXxTdM
 2 years ago

shivam_bhalla Group TitleBest ResponseYou've already chosen the best response.1
@QRAwarrior , i just remember this \[\int\limits_{}^{}\sqrt{x^2+a^2} = \frac{x}{2}\sqrt{x^2+a^2}+\frac{a^2}{2}\log{x+\sqrt{x^2+a^2}}+C\]
 2 years ago

shivam_bhalla Group TitleBest ResponseYou've already chosen the best response.1
You can go ahead and derive this
 2 years ago

shivam_bhalla Group TitleBest ResponseYou've already chosen the best response.1
I forgot the dx in the question :P
 2 years ago

QRAwarrior Group TitleBest ResponseYou've already chosen the best response.0
Ok, skrew that question and instead would you mind looking at this: You have the curves x = (y7)^2, and x = 4 that enclose a region. You must rotate this region about y = 5. dw:1337525316103:dw I need to use the shell method here, but it looks like as if I will get two cylinders here. Thanks for the help on the opening post question...
 2 years ago

experimentX Group TitleBest ResponseYou've already chosen the best response.1
I think that's formula for standard integral ... what do we call it ... i have bunch of them in my books ... but they are derived in the same way!!
 2 years ago

shivam_bhalla Group TitleBest ResponseYou've already chosen the best response.1
slight Correction: \[\int\limits\limits_{}^{}\sqrt{x^2+a^2} \space \space dx = \frac{x}{2}\sqrt{x^2+a^2}+\frac{a^2}{2}\log{x+\sqrt{x^2+a^2}}+C\]
 2 years ago

QRAwarrior Group TitleBest ResponseYou've already chosen the best response.0
@shivam_bhalla look at my recent post above
 2 years ago

QRAwarrior Group TitleBest ResponseYou've already chosen the best response.0
Those are two functions!
 2 years ago

QRAwarrior Group TitleBest ResponseYou've already chosen the best response.0
I just realized! I would have to use the washer.
 2 years ago

shivam_bhalla Group TitleBest ResponseYou've already chosen the best response.1
@QRAwarrior , I am not so good at this. @TuringTest can surely help you in this :)
 2 years ago

QRAwarrior Group TitleBest ResponseYou've already chosen the best response.0
Alright thanks your help for the above.
 2 years ago

QRAwarrior Group TitleBest ResponseYou've already chosen the best response.0
@TuringTest help please @amistre64 @Hero @asnaseer
 2 years ago

QRAwarrior Group TitleBest ResponseYou've already chosen the best response.0
@FoolForMath would you mind helping me here?
 2 years ago

QRAwarrior Group TitleBest ResponseYou've already chosen the best response.0
Someone is bound to come!
 2 years ago

QRAwarrior Group TitleBest ResponseYou've already chosen the best response.0
@apoorvk help please?
 2 years ago

QRAwarrior Group TitleBest ResponseYou've already chosen the best response.0
Please look at the most recent question (it is the one with the sketch just above, NOT THE OPENING POST)
 2 years ago

experimentX Group TitleBest ResponseYou've already chosen the best response.1
http://www.wolframalpha.com/input/?i=x+%3D+%28y7%29^2%2C++x%3D4 \[ \int_{5}^{9}2\pi (y7)(y7)^2 dy\]
 2 years ago
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