分离变量,各自积分
-∫x/(x^2+1)dx=∫1/(1+2y)dy
则-1/2ln(1+x^2)+lnC1=1/2ln(1+2y)
则有
2C1/(1+x^2)=(1+2y)
即
(1+x^2)(1+2y)=C
将变量x,y两边分,两边积分
-得到∫x/(x^2+1)dx=∫1/(1+2y)dy
=>-1/2ln(1+x^2)+lnC1=1/2ln(1+2y)
=>2C1/(1+x^2)=(1+2y)
=>(1+x^2)(1+2y)=C。
(1+2y)xdx = -(1+x^2)dy
dy/(1+2y) = -xdx/(1+x^2)
d(1+2y)/(1+2y) = -d(1+x^2)/(1+x^2)
ln(1+2y) = -ln(1+x^2) + lnC
(1+2y)(1+x^2) = C