I am new to the world of differential equations. I found this strange one on a PDF online. The excercise itself says that "Wolfram-Alpha won't help" and I cannot find any explanatory solution of it. Can you help me?
The equation is the following:
$$4y^3+7x\sin(x)+4x^4-\left(-\frac 74y^2+16\cos(y)-7x\right)\frac{dy}{dx} = -e^{-x+y}+\sinh(y)$$
Edit: I found it at this link (PDF). The exercise is the number 14. Actually, it only says "Challenge Task: solve the following differential equation"
Thank you, Dave