The solution of the differential equation dydx=sin(x+y)tan(x+y)−1 is
cosec(x+y)+tan(x+y)=x+c
x+cosec(x+y)=c
x+tan(x+y)=c
x+sec(x+y)=c
Put x+y=t→1+dydx=dtdx⇒∫cosectcottdt=∫dx⇒-cosec(x+y)+c=x