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how to integrate this

CodeCogsEqn.gif

how would you go about integrating this? The problem i encounter is dealing with the 1
Reply 1
Avatar for Zacken
Zacken
22
Original post by Icyytea
CodeCogsEqn.gif

how would you go about integrating this? The problem i encounter is dealing with the 1


Where is this problem from? Are you comfortable with substitutions?
Reply 2
Avatar for Icyytea
Icyytea
OP
5
my friend asked me it a while back and yeah i'm semi comfortable but idk how to deal with it
Reply 3
Avatar for Zacken
Zacken
22
Original post by Icyytea
my friend asked me it a while back and yeah i'm semi comfortable but idk how to deal with it


Could you post the rest of the question or the full question, please?
Reply 4
Avatar for Icyytea
Icyytea
OP
5
He told me I bet you can't integrate this then wrote it down on a piece of paper and handed it to me. Is it impossible to do with no further information given? It's not an official question he said he just came up with it when I asked him where it was from.
(edited 7 years ago)
Reply 5
Avatar for d3st1ny
d3st1ny
2
Just multiply out the 3y^2 to both sides, then split the LHS as all the y's and RHS as all the x's
Reply 6
Avatar for Smash98
Smash98
1
Balancing?
Reply 7
Avatar for Icyytea
Icyytea
OP
5
Original post by d3st1ny
Just multiply out the 3y^2 to both sides, then split the LHS as all the y's and RHS as all the x's


But then you're left with 3y^2 dy = 2xdx + 3y^2 dx, how do you deal with the last term (3y^2dx)?
Reply 8
Avatar for d3st1ny
d3st1ny
2
so 3y^2 (dy/dx) = 2x + 3y^2.

becomes... integral [3y^2] dy = integral [2x + 3y^2] dx

3y^3/3 = 2x^2/2 + 3xy^2

i think.
Original post by d3st1ny
so 3y^2 (dy/dx) = 2x + 3y^2.

becomes... integral [3y^2] dy = integral [2x + 3y^2] dx

3y^3/3 = 2x^2/2 + 3xy^2

i think.


nope, you can't integrate 3y^2 with respect to x, its a variable not a constant.
Reply 10
Avatar for Icyytea
Icyytea
OP
5
so it's impossible without other information such as y=...?
Reply 11
Avatar for kennz
kennz
8
Original post by Icyytea
so it's impossible without other information such as y=...?


yes
http://www.wolframalpha.com/input/?i=integrate+dy%2Fdx+%3D+2x%2F(3(y%5E2))+%2B1
Reply 12
Avatar for Zacken
Zacken
22
Original post by Icyytea
so it's impossible without other information such as y=...?


It's not a proper question.
Reply 13
Avatar for Icyytea
Icyytea
OP
5
Alright thanks I thought I was missing something major lol
Original post by Icyytea
CodeCogsEqn.gif

how would you go about integrating this? The problem i encounter is dealing with the 1


@Zacken

It is a valid differential equation, that's known as Chini's equation. However, Zacken is correct that it cannot be solved analytically - though it can be approximately solved using numerical methods, so you may want to look up Euler's method for example.
looks like your friend won the bet
Reply 16
Avatar for Zacken
Zacken
22
Original post by Katiee224
looks like your friend won the bet


What a cheat, though. :tongue:
Original post by Zacken
What a cheat, though. :tongue:


but this guy cheated by asking for help on a forum so nobodies perfect here:tongue:
Reply 18
Avatar for Zacken
Zacken
22
Original post by Katiee224
but this guy cheated by asking for help on a forum so nobodies perfect here:tongue:


Fair enough! :rofl:

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