Got Homework?
Connect with other students for help. It's a free community.
Here's the question you clicked on:
 0 viewing

This Question is Closed

ta123Best ResponseYou've already chosen the best response.1
hey you know on the other problem you were helping me with lagrange?
 2 years ago

ta123Best ResponseYou've already chosen the best response.1
what did you get for the answer because I got 4 and they counted it wrong
 2 years ago

LagrangeSon678Best ResponseYou've already chosen the best response.1
are u sure you evaluated correctly
 2 years ago

ta123Best ResponseYou've already chosen the best response.1
oh, made a stupid sign error
 2 years ago

ta123Best ResponseYou've already chosen the best response.1
could you help me with this new problem on the attachment
 2 years ago

LagrangeSon678Best ResponseYou've already chosen the best response.1
yeah let me look at it
 2 years ago

LagrangeSon678Best ResponseYou've already chosen the best response.1
okay so this is what you wanna do, set u=x+4, then you have to then rewrite x in terms of u. You can do this simply by saying x=u4
 2 years ago

LagrangeSon678Best ResponseYou've already chosen the best response.1
dw:1321490017407:dw
 2 years ago

LagrangeSon678Best ResponseYou've already chosen the best response.1
dw:1321490044699:dw
 2 years ago

LagrangeSon678Best ResponseYou've already chosen the best response.1
dw:1321490067161:dw
 2 years ago

ta123Best ResponseYou've already chosen the best response.1
do you replug the original function into u after integrating
 2 years ago

LagrangeSon678Best ResponseYou've already chosen the best response.1
yes after you, integrate, you must replace the orginal function
 2 years ago

ta123Best ResponseYou've already chosen the best response.1
did you get u^2/23x*2U^(1/2) after integrating
 2 years ago

LagrangeSon678Best ResponseYou've already chosen the best response.1
i led you wrong, my mistake. What you want to do, is let u=sqrt(x+4), now we rewrite x interm of u. To do this simply:dw:1321490856188:dw
 2 years ago

LagrangeSon678Best ResponseYou've already chosen the best response.1
okay, now you should get:dw:1321490948435:dw
 2 years ago

LagrangeSon678Best ResponseYou've already chosen the best response.1
now let fix up that integral:dw:1321491019469:dw
 2 years ago

LagrangeSon678Best ResponseYou've already chosen the best response.1
dw:1321491091199:dw
 2 years ago

LagrangeSon678Best ResponseYou've already chosen the best response.1
now recall that u=sqrt(x+4), thus we can divide out the u in the denmominator and the sqrt(x+4) as so:dw:1321491198348:dw The two can be put outside the integral since it is a constant
 2 years ago

LagrangeSon678Best ResponseYou've already chosen the best response.1
now simply we have:dw:1321491263984:dw
 2 years ago

LagrangeSon678Best ResponseYou've already chosen the best response.1
next you have to integrate that, and then replace the u's. Then evaluate over your limits
 2 years ago

LagrangeSon678Best ResponseYou've already chosen the best response.1
or, we could simply change the limits interms of u. Which would actaully be much eaier in this case. But i leave that up to you to decide on
 2 years ago

ta123Best ResponseYou've already chosen the best response.1
sqrt(x+4) did both cancel out and when you replace the u on the bottom back to x+4 don't you have to do the same thing to the top?
 2 years ago

LagrangeSon678Best ResponseYou've already chosen the best response.1
on top we had u^23, cause we replaced the x remeber
 2 years ago

ta123Best ResponseYou've already chosen the best response.1
oh, ok also you forgot to label the endpoints on the integral
 2 years ago

LagrangeSon678Best ResponseYou've already chosen the best response.1
well,i didnt forget, for me it is simpler to first leave the limits while i do the integration, since they really dont matter untill we get the antiderivative, which we then evlauate over the limits
 2 years ago

LagrangeSon678Best ResponseYou've already chosen the best response.1
yes i did,1 is the correct answer
 2 years ago

ta123Best ResponseYou've already chosen the best response.1
Thanks could you help me with one more of these problem?
 2 years ago

LagrangeSon678Best ResponseYou've already chosen the best response.1
did you post it already?
 2 years ago

LagrangeSon678Best ResponseYou've already chosen the best response.1
yeah, okay lets do this, can we multiply the x into the brackets, then seperate the integral into two spereate integrals:dw:1321500013159:dw
 2 years ago

LagrangeSon678Best ResponseYou've already chosen the best response.1
now lets take out some constants: dw:1321500075388:dw
 2 years ago

LagrangeSon678Best ResponseYou've already chosen the best response.1
now let try this, can we for the first integral, let x^2=u, then du=2xdx, which further means du/2x=dx
 2 years ago

LagrangeSon678Best ResponseYou've already chosen the best response.1
now it should look something like this:dw:1321500219046:dw
 2 years ago

LagrangeSon678Best ResponseYou've already chosen the best response.1
now we see that the x will divide out, and the 1/2 from the du can be taken outside the integral, so now we will get :dw:1321500319063:dw
 2 years ago

LagrangeSon678Best ResponseYou've already chosen the best response.1
now 2*1/2 is simply 1, so we now have:dw:1321500384165:dw
 2 years ago

LagrangeSon678Best ResponseYou've already chosen the best response.1
now we can integrate
 2 years ago

LagrangeSon678Best ResponseYou've already chosen the best response.1
for the first integral, what i the antiderivative of f'? well its simply f, the orginal function , and the second integral is very simpyle to integrate
 2 years ago

LagrangeSon678Best ResponseYou've already chosen the best response.1
dw:1321500486597:dw
 2 years ago

LagrangeSon678Best ResponseYou've already chosen the best response.1
dw:1321500522223:dw
 2 years ago

LagrangeSon678Best ResponseYou've already chosen the best response.1
but lets replace the u:dw:1321500561883:dw
 2 years ago

LagrangeSon678Best ResponseYou've already chosen the best response.1
now you can evaluate this over you limits but remeber that you were given certain conditions, namely f(1)=3 and f(0)=1.so we havedw:1321500688385:dw
 2 years ago

LagrangeSon678Best ResponseYou've already chosen the best response.1
furthermore:dw:1321500784828:dw
 2 years ago

ta123Best ResponseYou've already chosen the best response.1
yes, I was just was reviewing all the work, thanks!
 2 years ago

LagrangeSon678Best ResponseYou've already chosen the best response.1
anytime:)soon you will be an expert on calculus and you will be helping others as well
 2 years ago
See more questions >>>
Your question is ready. Sign up for free to start getting answers.
spraguer
(Moderator)
5
→ View Detailed Profile
is replying to Can someone tell me what button the professor is hitting...
23
 Teamwork 19 Teammate
 Problem Solving 19 Hero
 Engagement 19 Mad Hatter
 You have blocked this person.
 ✔ You're a fan Checking fan status...
Thanks for being so helpful in mathematics. If you are getting quality help, make sure you spread the word about OpenStudy.