Got Homework?
Connect with other students for help. It's a free community.
Here's the question you clicked on:
 0 viewing
Just another cute integral:
\[\int x^3 \; dx \]
and yes this is indefinite ;)
 one year ago
 one year ago
Just another cute integral: \[\int x^3 \; dx \] and yes this is indefinite ;)
 one year ago
 one year ago

This Question is Closed

Ishaan94Best ResponseYou've already chosen the best response.2
Hmm \[ \int x^2 = \left\{\begin{array}{kcc}\frac{1}{4}\cdot x^4, \quad x>0 \\ 0, \quad x = 0 \\ \frac{1}{4}x^4, \quad x<0 \end{array}\right.\]Maybe?
 one year ago

FoolForMathBest ResponseYou've already chosen the best response.0
I have never seen a indefinite integral represented like this.
 one year ago

Ishaan94Best ResponseYou've already chosen the best response.2
Me neither but I never had to integrate modulus functions without limits before. It has to be like this, I am quite sure.
 one year ago

shivam_bhallaBest ResponseYou've already chosen the best response.1
\[\int\limits_{}^{}x^3 dx = \frac{x^3*x}{4}+c\] I hope this is right @FoolForMath and congrats on being a new moderator
 one year ago

Ishaan94Best ResponseYou've already chosen the best response.2
This can't be right, x stays positive but the x^3 can get negative.
 one year ago

Ishaan94Best ResponseYou've already chosen the best response.2
I am not sure though. and I can be wrong.
 one year ago

shivam_bhallaBest ResponseYou've already chosen the best response.1
For negative x , x = x and therfore integral value would be positive. Though I can be wrong @ this
 one year ago

Ishaan94Best ResponseYou've already chosen the best response.2
For negative x, x^3 * x = (x)^3 ((x)) = x^4
 one year ago

Ishaan94Best ResponseYou've already chosen the best response.2
What's wrong piece wise representation?
 one year ago

Ishaan94Best ResponseYou've already chosen the best response.2
wait... my piece wise is gonna give same result as yours
 one year ago

Ishaan94Best ResponseYou've already chosen the best response.2
so, either we are both wrong or right
 one year ago

shivam_bhallaBest ResponseYou've already chosen the best response.1
\[\huge \int\limits\limits_{}^{}x^3 dx = {sgn(x)}* \frac{x^4}{4}+c\]
 one year ago

Ishaan94Best ResponseYou've already chosen the best response.2
and your integral does seems better
 one year ago

Ishaan94Best ResponseYou've already chosen the best response.2
sgn(x) how could i not think about it!?!?! :(
 one year ago

Ishaan94Best ResponseYou've already chosen the best response.2
so, there are multiple ways of representing same integral?
 one year ago

Ishaan94Best ResponseYou've already chosen the best response.2
because every integral on this page is gonna get you the same result
 one year ago

Ishaan94Best ResponseYou've already chosen the best response.2
so, how do you rule out others? and make one right.
 one year ago

shivam_bhallaBest ResponseYou've already chosen the best response.1
@Ishaan94 , Is my integral right because substitute x and check please
 one year ago

Ishaan94Best ResponseYou've already chosen the best response.2
x^4/4 is what we will get. sgn(x)x^4/4 = 1* x^4/4
 one year ago

shivam_bhallaBest ResponseYou've already chosen the best response.1
Yes and why is it negative??
 one year ago

shivam_bhallaBest ResponseYou've already chosen the best response.1
I have confused myself lolol
 one year ago

Ishaan94Best ResponseYou've already chosen the best response.2
i am confused myself and blabbering :/
 one year ago

shivam_bhallaBest ResponseYou've already chosen the best response.1
Same here LOL. However I wolframed it and it is giving my equation. The sgn(x) one. Ditto . ??
 one year ago

shivam_bhallaBest ResponseYou've already chosen the best response.1
Ok I got it. Taking example always helps
 one year ago

shivam_bhallaBest ResponseYou've already chosen the best response.1
In that case how is my first equation wrong , the very first one I mentioned ??
 one year ago

Ishaan94Best ResponseYou've already chosen the best response.2
\[\int_{1}^1 x^3 = \int_{1}^0 x^3 + \int_{0}^1 x^3 = (1/4) + \frac14 = \frac12 \] \[\left[sgn(x) \cdot \frac{x^4}{4}\right]_{1}^1 = \frac{1}4 + \frac14\]
 one year ago

Ishaan94Best ResponseYou've already chosen the best response.2
Your first integral was right as well
 one year ago

Ishaan94Best ResponseYou've already chosen the best response.2
My piece wise representation is pelletty :/
 one year ago

shivam_bhallaBest ResponseYou've already chosen the best response.1
Haha. Maths always confuses us even when we have the right answers . :P
 one year ago

Ishaan94Best ResponseYou've already chosen the best response.2
yeah hahaha i never had to integrate such indefinite integrals before.
 one year ago

Ishaan94Best ResponseYou've already chosen the best response.2
Why isn't FoolForMath replying?
 one year ago

shivam_bhallaBest ResponseYou've already chosen the best response.1
Only 2 people know the answer to your question @Ishaan94 , @FoolForMath and god himself :P
 one year ago

FoolForMathBest ResponseYou've already chosen the best response.0
Lol, I had the answer but I only figured it out why is it working. Thanks to M.se again ;)
 one year ago

Ishaan94Best ResponseYou've already chosen the best response.2
I beat God! by 455 fans
 one year ago

FoolForMathBest ResponseYou've already chosen the best response.0
So, the answer is \[ \frac 1 4 x^3 \cdot x +C \]
 one year ago

shivam_bhallaBest ResponseYou've already chosen the best response.1
Does it matter, @FoolForMath the position of modulus on either x^3 or x :P
 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.