True, Thanks for watching till the end. Also suggested by one of our subscriber: "However you wrote the final solution with x+y as the denominator by accident, even though you did state it was x+4y." I normally do not edit my videos and mistakes happen. The idea is to enjoy the journey of sharing and learning!
what is the product rule of the (xy) then ? i dont know pls let me know i may also tell the wrong question for the reason of not knowing much thanks for you time sir