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

wioBest ResponseYou've already chosen the best response.1
It's a rational polynomial, have you tried factoring it?
 one year ago

monroe17Best ResponseYou've already chosen the best response.0
let me do it real quick
 one year ago

monroe17Best ResponseYou've already chosen the best response.0
it cant be factored..
 one year ago

AnElephantBest ResponseYou've already chosen the best response.0
imaginary roots wont help you in this i think... hold on... (props for a challenging question)
 one year ago

wioBest ResponseYou've already chosen the best response.1
You said it can't be factored... what are the roots of the denominator?
 one year ago

wioBest ResponseYou've already chosen the best response.1
rational functions like this often don't have elementary anti derivatives.
 one year ago

wioBest ResponseYou've already chosen the best response.1
Is this a homework problem?
 one year ago

monroe17Best ResponseYou've already chosen the best response.0
it's a practice problem for my exam this coming thursday. I'm trying to study and get familiar with the problems.
 one year ago

AnElephantBest ResponseYou've already chosen the best response.0
ok got it, in this type of question you need to rewrite it so that at least one of the parts of the numerator is equal to the derivative of the denominator. So we may rewrite it like so: 31/5 integral(1/5x^24x+1) +3/10 integral((10x4)/(5x^24x+1)) Use u substitution for integral((10x4)/(5x^24x+1)) u= the denominator and du = the numerator So now you get 3/10 1/u du (which is also the same as 3/10 ln(u) Now substitute x back into u Now, rewrite the other part of the integral (complete the square) to find an inverse tan function hidden there. It simplifies to the equation 31/5 (arctan(25x) so the final equation is : 3/10 ln(5x^24x+1) + 31/5 (arctan(25x) +c (do NOT forget the +C after all this work lol)
 one year ago

AnElephantBest ResponseYou've already chosen the best response.0
if you want a more insightful thought process of a certain part of a problem, please ask (i was kinda just in a hurry to get it done)
 one year ago

monroe17Best ResponseYou've already chosen the best response.0
woah woah, explain how you rewrote it.. i dont get that..
 one year ago

AnElephantBest ResponseYou've already chosen the best response.0
Okay, so, we know the derivative of the denominator is 10x4 right? so we just have to do a lot of algebra to get at least one part of the numerator to look like that (its mostly a lucky guess in my case) because i had in the back of my mind that a problem as complex as this needs to use u substitiution
 one year ago

monroe17Best ResponseYou've already chosen the best response.0
so, i have to get the numerator to be 10x4? (which is the derivative of the denom)
 one year ago

AnElephantBest ResponseYou've already chosen the best response.0
3x+5 = 31/5 + 3/10 (10x4) ; (the 2 numerators of the integrals before i factored out constants
 one year ago

AnElephantBest ResponseYou've already chosen the best response.0
Yes, in a problem where there is a denominator, you need to first think of substitution and how you can get the derivative of the denominator into the numerator of the function
 one year ago

monroe17Best ResponseYou've already chosen the best response.0
I still don't get how in the worl you get 31/5+3/10(10x4)... out of 3x+5
 one year ago

AnElephantBest ResponseYou've already chosen the best response.0
ok, so, we need to get 10x4 out of this so : 3x+5 = 30x+50, then subtract 3(10x4) to get a remainder of 62 (this will go in the 2nd integral)
 one year ago

AnElephantBest ResponseYou've already chosen the best response.0
keep in mind, this is all over a denominator of 10 (which we inserted into the equation when we multiplied 3x+5 by 10)
 one year ago

monroe17Best ResponseYou've already chosen the best response.0
so multiply by ten and subtract 3(10x5)?
 one year ago

AnElephantBest ResponseYou've already chosen the best response.0
yeah, and hope you get lucky later on ; )
 one year ago

monroe17Best ResponseYou've already chosen the best response.0
how do you subtract 3(10x5) from 30x+50? lol! im so sorry... i just really dont understand
 one year ago

AnElephantBest ResponseYou've already chosen the best response.0
no problem, ive been told i make a horrible teacher XD (and it's 3(10x4) So, 30x+50  3(10x4) = 30x+50  30x + 12 which makes 62 (the constant in the 2nd integral) then you simply divide by 10 to get 31/5 which is what i factored out of the integral
 one year ago

monroe17Best ResponseYou've already chosen the best response.0
ahhh, got it,. what you mean constant in the 2nd integral,. ?
 one year 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.