Question

The integrating factor of the differentiable equation
` (xy-1)(dy)/(dx)+y^(2) =0` is
A. `1/x`
B. `1/y`
C. `1/(xy)`
D. xy

Answer 1

Correct Answer - b
The given equation can be written as
` xy dy + y^(2) dx - dy =0`
` rArr x dy + y dx - 1/y dy = 0`
` rArr d (xy) = (dy)/y`
` rArr int d (xy) = int (dy)/y`
`rArr xy - log y = C`
` rArr 1/y` is integrating factor .