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Share/Save/Bookmark Login/ Register to Bookmark Topic : "DIFFERNTIAL ( TASTE UR SKILL )" Started by Manmay

Manmay

#1 Posted 7:25pm 05-03-10  

DIFFERNTIAL ( TASTE UR SKILL )

1) cos (x+y) dy = dx
2) [frac]x+y[frac]dy[/]dx[/frac][/]y-x[frac]dy[/]dx[/frac][/frac] = (1 + [frac]x[p]2[/p][/]y[p]2[/p][/frac]) ( ln ( x[p]2[/p]+y[p]2[/p] ))
3) [frac]dy[/]dx[/frac] = (4x + y + 1)[p]2[/p]
4) 2x[p]3[/p]y[p]3[/p] + x[p]4[/p]y[p]2[/p] [frac]dy[/]dx[/frac] = [frac]-b[p]2[/p][/]a[p]2[/p][/frac]y - [frac]b[p]2[/p][/]a[p]2[/p][/frac] x [frac]dy[/]dx[/frac]


[ GUYS POST THE SOLN. FULL AS I CANNOT CONFIRM UR  ANS. SINCE I DON'T HAVE THEM ]
In every loss, in every lie, in every truth that you'd deny And each regret and each goodbye was a mistake too great to hide And your voice was all I heard that I get what I deserve    

govind

#2 Posted 7:34pm 05-03-10  

Re: DIFFERNTIAL ( TASTE UR SKILL )

For the first one...substitute x + y = t...
in the third substitute 4x + y + 1 = t..
for the fourth one on observation it looks like the equation is x[p]4[/p]y[p]3[/p] = -b[p]2[/p]/a[p]2[/p] xy + c...par LHS main coefficients stidfy nahi ho rahey..  : (
 Edited on 7:45pm 05-03-10    

govind

#3 Posted 7:52pm 05-03-10  

Re: DIFFERNTIAL ( TASTE UR SKILL )

cost = dx/dy ....
x + y = t
diff. wrt to y
dx/dy + 1 = dt/dy
cost + 1 = dt/ dy..
now integrate it...write cost in terms of tant/2
cost = 1-tan[p]2[/p]t/2 / 1+tan[p]2[/p]t/2
 Edited on 7:57pm 05-03-10    

Tapas

#4 Posted 8:03pm 05-03-10  

Re: DIFFERNTIAL ( TASTE UR SKILL )

[im]http://www4a.wolframalpha.com/Calculate/MSP/MSP382199fc9i7hh7g204e00005abh0597icff582e?MSPStoreType=image/gif&s=18&w=229&h=36[/im]

OR

[im]http://www4a.wolframalpha.com/Calculate/MSP/MSP385199fc9i7hh7g204e00005h29ic2ba2h07efg?MSPStoreType=image/gif&s=18&w=207&h=36[/im]
   

Manmay

#5 Posted 8:04pm 05-03-10  

Re: DIFFERNTIAL ( TASTE UR SKILL )

3) [frac]dt[/]dx[/frac] = t[p]2[/p] + 4.
   [frac]dt[/]t[p]2[/p] + 4[/frac] = dx.
  x = [frac]1[/]2[/frac] tan [p]-1[/p] ([frac]t[/]2[/frac])
 x = [frac]1[/]2[/frac] tan [p]-1[/p] ([frac]4x + y + 1[/]2[/frac])





WAT ABT THE 2ND ONE????????
In every loss, in every lie, in every truth that you'd deny And each regret and each goodbye was a mistake too great to hide And your voice was all I heard that I get what I deserve    

Tapas

#6 Posted 8:16pm 05-03-10  

Re: DIFFERNTIAL ( TASTE UR SKILL )

@ Manmay

in 1 tan t/2 = t
   

Avik

#7 Posted 8:25pm 05-03-10  

Re: DIFFERNTIAL ( TASTE UR SKILL )

[im]http://codecogs.izyba.com/gif.latex?Q2%29%20%5C%20My%20%5C%20start...%5C%5C%20y/x%20%3Dt%20%3D%3E%20y%27%20%3D%20x.t%27+t%5C%5C%20%5C%5C%20%5Cleft%5B%201+%20t%20%5Cleft%28x.%5Cfrac%7Bdt%7D%7Bdx%7D+t%5Cright%29%5Cright%5D%20%3D%20%5Cleft%28-x.%5Cfrac%7Bdt%7D%7Bdx%7D%7D%5Cright%29%5Cleft%281+%20%5Cfrac%7B1%7D%7Bt%7D%5Cright%29%5Cleft%5B2ln%28x%29+%20ln%281+t%5E2%29%5Cright%5D[/im]

Which reduces to....

[im]http://codecogs.izyba.com/gif.latex?%5Cfrac%7Bdt%7D%7Bdx%7D%5Cleft%5B%20t+%20ln%281+t%5E2%29%5E%7B1+1/t%7D%20+%20ln%28x%29%5E%7B2/t%20+2%7D%5Cright%5D%20+%20%5Cfrac%7B%281+t%5E2%29%7D%7Bx%7D%20%3D%200[/im]

Now, if this can be converted to a linear one; ...can't see ny phurther....
...... Shielding the past, move on ......... Fearless, confident, gleaming, rejoicing ......... Knowing tht u can & knowing tht u will ...... Knowing tht fighting along is the only pill.    

Manmay

#8 Posted 4:13pm 06-03-10  

Re: DIFFERNTIAL ( TASTE UR SKILL )

i can't help it. please any one solve 2) and 4)
In every loss, in every lie, in every truth that you'd deny And each regret and each goodbye was a mistake too great to hide And your voice was all I heard that I get what I deserve    

Manmay

#9 Posted 4:17pm 06-03-10  

Re: DIFFERNTIAL ( TASTE UR SKILL )

4) ANS IS.....x[p]3[/p]y[p]2[/p] - cxy = [frac]b[p]2[/p][/]a[p]2[/p][/frac]   where c is constant.
In every loss, in every lie, in every truth that you'd deny And each regret and each goodbye was a mistake too great to hide And your voice was all I heard that I get what I deserve    

b_k_dubey

#10 Posted 8:09pm 25-03-10  

Re: DIFFERNTIAL ( TASTE UR SKILL )

4) Divide whole equation by x[p]2[/p]y[p]2[/p] and multiply by dx

[im]http://codecogs.izyba.com/gif.latex?2xydx+x^{2}dy=-\frac{b^2}{a^2}\frac{ydx+xdy}{x^2y^2}[/im]

[im]http://codecogs.izyba.com/gif.latex?yd(x^2)+x^{2}dy=-\frac{b^2}{a^2}\frac{d(xy)}{x^2y^2}[/im]

[im]http://codecogs.izyba.com/gif.latex?d(x^2y)=-\frac{b^2}{a^2}\frac{d(xy)}{x^2y^2}[/im]

integrate : [im] http://codecogs.izyba.com/gif.latex?x^2y=-\frac{b^2}{a^2}\left(-\frac{1}{xy}%20\right)+c[/im]

[im]http://codecogs.izyba.com/gif.latex?x^2y^2-cxy=\frac{b^2}{a^2}[/im]

..    

Zuko

#11 Posted 9:40pm 25-03-10  

Re: DIFFERNTIAL ( TASTE UR SKILL )

2)
[im]http://codecogs.izyba.com/gif.latex?\frac{x+y\frac{dy}{dx}}{y-x\frac{dy}{dx}}=\left(1+\frac{x^2}{y^2}%20\right)ln(x^2+y^2)%20\\%20\\\frac{xdx+ydy}{ydx-xdy}=\left(1+\frac{x^2}{y^2}%20\right)ln(x^2+y^2)%20\\%20\\\frac{xdx+ydy}{\frac{ydx-xdy}{y^2}}=\left(x^2+y^2%20\right)ln(x^2+y^2)%20\\%20\\\frac{d(x^2+y^2)}{\left(x^2+y^2%20\right)ln(x^2+y^2)}=d\left(\frac{x}{y}%20\right)[/im]

Now take:
[im]http://codecogs.izyba.com/gif.latex?x^2+y^2=z%20\\\\and,\:%20\frac{x}{y}=t%20\\\\equn.\:%20becomes:%20\frac{dz}{zlnz}=dt%20\\\\or,\:%20ln(ln(z))=t+c%20\\\\solution:\:%20ln(ln(x^2+y^2))=\frac{x}{y}+c%20\\\\or,\:ln(x^2+y^2)=ke^{\frac{x}{y}}[/im]
Keyboard is mightier than the sword.  Edited on 9:41pm 25-03-10    

Manmay

#12 Posted 08:45am 26-03-10  

Re: DIFFERNTIAL ( TASTE UR SKILL )

thnks everyone
In every loss, in every lie, in every truth that you'd deny And each regret and each goodbye was a mistake too great to hide And your voice was all I heard that I get what I deserve    
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