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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.
 one year ago
 one year ago
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.
 one year ago
 one year ago

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Mimi_x3Best ResponseYou've already chosen the best response.0
Then where do you needhelp with?
 one year ago

QRAwarriorBest ResponseYou've already chosen the best response.0
Where do you people get your bike avatars from?
 one year ago

QRAwarriorBest ResponseYou've already chosen the best response.0
I do not want "Google" as an answer... :O
 one year ago

lgbasalloteBest ResponseYou've already chosen the best response.0
looks trig sub...have you learned that yet?
 one year ago

lgbasalloteBest ResponseYou've already chosen the best response.0
but we really did gust google this! i swear! :(
 one year ago

Mimi_x3Best ResponseYou've already chosen the best response.0
What's the whole question?
 one year ago

lgbasalloteBest ResponseYou've already chosen the best response.0
dw:1337521244254:dw
 one year ago

QRAwarriorBest ResponseYou've already chosen the best response.0
dw:1337521266266:dw
 one year ago

QRAwarriorBest ResponseYou've already chosen the best response.0
Yes I know that trig sub.
 one year ago

lgbasalloteBest ResponseYou've already chosen the best response.0
dw:1337521291094:dw
 one year ago

QRAwarriorBest 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?
 one year ago

Mimi_x3Best ResponseYou've already chosen the best response.0
the problem is subbing in the limits???
 one year ago

LagrangeSon678Best ResponseYou've already chosen the best response.1
convert the limits when using the trig sub
 one year ago

lgbasalloteBest ResponseYou've already chosen the best response.0
dont forget to change back to x before evaluating
 one year ago

Mimi_x3Best ResponseYou've already chosen the best response.0
No, you don't need to convert back
 one year ago

lgbasalloteBest ResponseYou've already chosen the best response.0
otherwise you'll have to convert the limits in terms of theta
 one year ago

QRAwarriorBest 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
 one year ago

lgbasalloteBest ResponseYou've already chosen the best response.0
yep.. \[\int \sec^3 \theta d\theta\]
 one year ago

QRAwarriorBest ResponseYou've already chosen the best response.0
Then what is limits of integration wrt θ?
 one year ago

QRAwarriorBest ResponseYou've already chosen the best response.0
What is arctan(4)?
 one year ago

QRAwarriorBest ResponseYou've already chosen the best response.0
How did you get that?
 one year ago

lgbasalloteBest ResponseYou've already chosen the best response.0
it was sec^3 theta...ohh woops
 one year ago

lgbasalloteBest 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
 one year ago

QRAwarriorBest ResponseYou've already chosen the best response.0
dw:1337523905957:dw @LagrangeSon678 @shivam_bhalla
 one year ago

experimentXBest ResponseYou've already chosen the best response.1
evaluate it individually .. \[ \int \sec \theta d\theta = \ln \sec\theta + \tan\theta\]
 one year ago

experimentXBest ResponseYou've already chosen the best response.1
this is a lot better http://answers.yahoo.com/question/index?qid=20110524035942AAXxTdM
 one year ago

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

shivam_bhallaBest ResponseYou've already chosen the best response.1
You can go ahead and derive this
 one year ago

shivam_bhallaBest ResponseYou've already chosen the best response.1
I forgot the dx in the question :P
 one year ago

QRAwarriorBest 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...
 one year ago

experimentXBest 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!!
 one year ago

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

QRAwarriorBest ResponseYou've already chosen the best response.0
@shivam_bhalla look at my recent post above
 one year ago

QRAwarriorBest ResponseYou've already chosen the best response.0
Those are two functions!
 one year ago

QRAwarriorBest ResponseYou've already chosen the best response.0
I just realized! I would have to use the washer.
 one year ago

shivam_bhallaBest ResponseYou've already chosen the best response.1
@QRAwarrior , I am not so good at this. @TuringTest can surely help you in this :)
 one year ago

QRAwarriorBest ResponseYou've already chosen the best response.0
Alright thanks your help for the above.
 one year ago

QRAwarriorBest ResponseYou've already chosen the best response.0
@TuringTest help please @amistre64 @Hero @asnaseer
 one year ago

QRAwarriorBest ResponseYou've already chosen the best response.0
@FoolForMath would you mind helping me here?
 one year ago

QRAwarriorBest ResponseYou've already chosen the best response.0
Someone is bound to come!
 one year ago

QRAwarriorBest ResponseYou've already chosen the best response.0
@apoorvk help please?
 one year ago

QRAwarriorBest 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)
 one year ago

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