Differential Vs. Derivative fail

[Gio1604]

Hi guys, was wondering about your opinion.
Took calc 1 exam with the following question given in dutch: Find differential of the function y = arccos(x^2)ln x. See attached pic. Stupid me misread it into deriving the function in dy/dx = f(x)' rather than dy = f(x)' dx....
My answer is on the left side, correct answer is on the right side. Note that the only difference in the the placement of the DX. In my answer DX is left to the equation (in form dy/dx = f(x)') while the professors answer the DX is on the right side (dy = f(x)' dx).


Is there any argument I could use to convince the professor to still give me marks for this?
Only 18% passed the exam and Im this one little point off to join that 18%??

Thanks for reading and to anyone who replies

 

[Dr.Peterson]

Were you given no credit, or just lost a point for the missing dx?

You certainly can't get full credit when you gave a derivative rather than the differential called for. But I would give credit for the rest of your work (assuming partial credit is allowed in the course). The argument is that you did that work. His argument back could be that the whole point was to test your knowledge of what a differential is.

 

[Gio1604]

Thanks Dr. Peterson,
Managed to get 1 out of 2 points but originally but your reasoning that the whole point is to test the difference between differential and derivative makes sense. This course had past papers going back 5 years now and not a single time did they ask the differential (always derivative), I should've read the question with more care. Thanks for your insight, saved me from sending a pretty embarrassing email to my professor..

 

[Steven G]

The derivative/differential was not so simple. That is, the problem was not only to know where to put the dx. The real problem is that you got 1 out of 2 points. I would have given you 80% of the point value. The problem with low point valued problem is that Professor's will usually only give 0, 1 or 2 points and (unfortunately) not 1.6 points (which is 80% of 2 points).

I had a professor for complex analysis who would give very strange exams where the total point value would be 28 or 34 or 29, random values. Now if I made a stupid arithmetic mistake she would take of 1 point. The problem is that the 1 point was not 1%, sometimes it was over 5%. This almost caused me to lose my grade of A.

If you are only one point away from passing then you can speak with your professor stating that you misread the problem. The real question is if being on the passing side for this exam will really help you that much? If 60% is passing and you got a 59% it will really not have a big impact on your final grade.