y''=siny+cosy=√2sin(y+π/4)
设y'=p y''=pdp/dy
pdp=√2sin(y+π/4)dy
p²=C1-2√2cos(y+π/4)
P=±√[C1-2√2cos(y+π/4)]
dy/√[C1-2√2cos(y+π/4)]=±dx
积分得通x=±∫dy/√[C1-2√2cos(y+π/4)]+C2
y''=siny+cosy=√2sin(y+π/4)
设y'=p y''=pdp/dy
pdp=√2sin(y+π/4)dy
p²=C1-2√2cos(y+π/4)
P=±√[C1-2√2cos(y+π/4)]
dy/√[C1-2√2cos(y+π/4)]=±dx
积分得通x=±∫dy/√[C1-2√2cos(y+π/4)]+C2