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

Andras Group TitleBest ResponseYou've already chosen the best response.1
This is a hard one x^2+8x+25=(x+4)^2+9 so use sub u=x+4 du=dx New integral: 1/(u^2+9)^0.5
 3 years ago

nubeer Group TitleBest ResponseYou've already chosen the best response.0
hmmm ya i also reached at this point but what after this?
 3 years ago

Andras Group TitleBest ResponseYou've already chosen the best response.1
thinking of the next substitution, maybe some trig function
 3 years ago

nubeer Group TitleBest ResponseYou've already chosen the best response.0
hmm yes i think that would be tan but how and why
 3 years ago

Andras Group TitleBest ResponseYou've already chosen the best response.1
I know! Recall that tan^2(x)+1=sec^2(x)
 3 years ago

Andras Group TitleBest ResponseYou've already chosen the best response.1
so we need to make 9tan^2(x) from u to get 9(tan^2(x)+1)
 3 years ago

Andras Group TitleBest ResponseYou've already chosen the best response.1
let u=3tan(z) du=3sec^2(z) dz
 3 years ago

Andras Group TitleBest ResponseYou've already chosen the best response.1
So the integral will be: 3sec^2(z)/3sec(z)=sec(z)
 3 years ago

Andras Group TitleBest ResponseYou've already chosen the best response.1
What the integral of secz? log(tanz+secz) (just looked it up)
 3 years ago

Andras Group TitleBest ResponseYou've already chosen the best response.1
we have u=3tanz expressing z=tan^1(u/3)
 3 years ago

nubeer Group TitleBest ResponseYou've already chosen the best response.0
thanks man.. well pretty much hit the answer but can u explain this 1 step let u=3tan(z) du=3sec^2(z) dz.. why we suppose 3 tan(z) why not just tan
 3 years ago

Andras Group TitleBest ResponseYou've already chosen the best response.1
because if it is 3tan than (3tan)^2=9tan^2(x) so we can factor out 9 to get 9(tan^2(x)+1)
 3 years ago

nubeer Group TitleBest ResponseYou've already chosen the best response.0
ohh so just that was the reason to put 3?
 3 years ago

Andras Group TitleBest ResponseYou've already chosen the best response.1
Hope it helped, now you just need to plug back the z and u to get x
 3 years ago

FoolForMath Group TitleBest ResponseYou've already chosen the best response.0
do you know about hyperbolic functions ?
 3 years ago

FoolForMath Group TitleBest ResponseYou've already chosen the best response.0
sinhx ?
 3 years ago

FoolForMath Group TitleBest ResponseYou've already chosen the best response.0
and this is a elementary problem no need to think hard on this one
 3 years ago

Andras Group TitleBest ResponseYou've already chosen the best response.1
e^x+e^x/2 how would that help?
 3 years ago

Zarkon Group TitleBest ResponseYou've already chosen the best response.0
\[\frac{d}{dx}\operatorname{arsinh}(x) =\frac{1}{\sqrt{x^{2}+1}}\]
 3 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.