Slve the differential equations - ydx - xdy

Question

Solve the following differential equations:

1. √(1- x² )dy + √(1- y² )dx = 0

2. x√(1+ y² )dx + y√(1 + x²)dy = 0

3. (1+ x)ydx + (1+ y)xdy = 0

4. (1+ x²)dy = (1+ y²)dx

5. log (dy/dx) = ax + by

6. ydx - xdy = xydx

7. dy/dx = (1+ x)y²/dx (y - 1)x²

8. dy/dx = x(2 log x + 1)/(siny + y cosy)

9. dy/dx = e^x-y + + x²e^-y

10. (ex +1)ydy = (y +1)e^x dx

11. 3e^x tan ydx + (1- e^x) sec² ydy = 0

12. sec² x.tanydx + sec² y tan xdy = 0