- #1
mattbonner
- 14
- 0
Homework Statement
(4y4-9x2y2-144)dx - (5xy3)dy = 0
Homework Equations
substitute y = xv
dy = dx v + dv x
The Attempt at a Solution
after substituting i got
(4x4v4-9v2x4-14x4)dx - (5v3x4)dx.v + dv.x
= (4v4-9v2-14)dx - 5v3(dx.v + dv.x) = 0
= dx(4v4-9v2-14-5v4)+dv(-5v3x)= 0
dx/x = (-5v3dv)/(v4-9v2-14)
dx/x = ((2v)/(v2+2) - (7v)/(v2+7)) dv
derive both sides
ln(x) = ln(v2+2) - 3.5ln(v2+7)
x + c = (v2+2) / (v2+7)3.5
c = (((y/x)2+2) / ((y/x)2+7)3.5) - x
what am i doing wrong?