Solve the Initial Value Problem
\[x^{2}\frac{ dy }{ dx}=\frac{ 4x^{2}-x-2 }{ (x+1)(y+1) } ,y(1)=1\]
please write step by step, im sorry
\[(y+1) dy =\frac{4x^2-x-2}{x^2(x+1)}dx \] Ok?
i get that
integral both sides. That's it
okay please bear with me, as it can get crazy
im working on it
I guess so, but that the steps after getting the answer, replace initial value to get value of C, then plug back
okay give me 10000 seconds please
\[\int\limits_{}^{}\frac{ 4x ^{2}-x-2 }{ x ^{2}(x+1) }dx\]
it has already gotten crazy
use partial fraction, friend
could you do a quick refresher, my apologies as it has been last last year doing this
\[\frac{4x^2-x-2}{x^2(x+1)}=\frac{A}{x+1}+\frac{B}{x}+\frac{C}{x^2}\] solve for A, B, C you have A = 3, B =1, C =-2 so, the integral becomes \[\int( \frac{3}{x+1}+\frac{1}{x}-\frac{2}{x^2})dx\] then take integral each term to get the answer
light BULB! thank you!
ok
im sorry for making you work that out
np.
nevermind!
how do you integrate the y part?
do as usual, = \(\dfrac{y^2}{2}+y\)
i got 3ln(x+1)+lnx+2/x for the other side thank you
+ C
so i got y^2x/2+y=3ln(x+1)+lnx+2/x+c
yes, I think so
no, y^2 /2, not y^2x/2
you're right my bad
and then solve for y?
solve for C
replace initial value y(1) =1 to solve for c
so plug 1 in for y? im sorry
first off, you have to solve for y . I am sorry, it's not easy but we have an outlet there y^2 + 2y - 2( the whole thing from the left hand side) =0 . This is a quadratic equation, you solve for y, so, y = ....( 2 values) then, plug x =1 into this y and the whole thing = 1 because y(1) =1 to solve for c
because from the differential equation above, your answer is y^2/2 +y , not just y, So, you have to solve for y , and then calculate the initial value base on the latest y
gotta go. be back later.
thanks
hey, you see, wolfram solves this problem exactly our way, hehehe http://www.wolframalpha.com/input/?i=x^2%28dy%2Fdx%29%3D%284x^2-x-2%29%2F%28%28x%2B1%29%28y%2B1%29%29
how does wolfram jump from x^2(dy/dx)=(4x^2-x-2)/((x+1)(y+1) to the long equation with y(x)?
don't you scrool up? it solves the problem at the beginning of the problem, drag the bar up to see the very first step
i don't have an account for that
i don't see it
can you read it?
yes i can
but how do they get from 1/2 y^2+y=3ln(x+1)+lnx+2/x+c to the longer equation with y(x)
hey, don't be panicked. I told you , it's a quadratic , see -1 at the end of each y the equation is \[y^2 +2y -(6ln(x+1)+lnx +\frac{2}{x}+C) =0\]
so, \[ y = \frac{-2\pm\sqrt {2^2-4*1*(the~~whole~bracket)}}{2}\]
got it?
it's a lot to take in
yes, but we are on the right track, right? lalalaala from these, plug x =1 and y =1 into them to have C
It is the beginning of the semester, right?
sorry!
because there is a lot for you to delete.
yes
jamal is a boy name in america
con trai
not yet :( school first
that's good, son
tại sao tên của dì loser66?
How do you understand the word of "Loser"?? 66 is my born year
cảm ơn rất nhiều! nghe có vẻ rất tốt đẹp
Please, speak English!! Your Vietnamese is ridiculous as my English. hehehe
you said that sentence very well! hahaha
And don't forget correct my English, please
including vocabulary.
And don't forget to correct my English, please
It's getting late now and I have class tomorrow morning. Thank you for helping me with math, it was nice getting you to know you! I will see you soon when I have new questions, which I will. Good night!
you can send it from here
ok
Thank you very much!
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