I survived my oral math exam!!! Yeah! But my math teacher picked the three two-quarters I was not good, he just did not made a task about the topics in the two quarters I had 10 points (B-). Dumbass! It wasn’t even necessary that he uses the topics of three two quarters, of two two-quarters would have been enough. I saw the tasks and I did not know what to do. In the end, I solved all seven tasks, somehow. For most of them the result seemed wrong. First I had to tell two characteristics why the graph shows the cup from the pic and I had to calculate the maximal diameter. The graph given was shown from x=0 to x=8 and at 8 it had the biggest diameter (I knew it because of the picture given) so I just plugged in the 8 for the x in the function.
Second, I had to draw a circle with the given centre and the givenvents intersection with the graph. Fortunately I brought my spring bow. So I delineated it into the coordinate system. Because of the spring bow and the given points I knew the radius and I was able to set up the equation for the circle.
Next, I had to describe how I can calculate the radius exactly.
Then I had to check if the condition f(3)<0,25 is correct so I had to set up the derivation and insert 3 for x.
The next one consisted of the calculating method and I had to explain what is happening in each step (it was about the volume of revolution)
Then I had to draw a tree diagram about twenty cappuccinos, 14 of them with, 6 without cocoa. From the 14 with cocoa the judges marked them as good with a 70% probability but the ones without only with a probability of 55% and calculate the probability for a cappuccino regardless if it was with or without cocoa to be marked as good.
Last I had to calculate the probability for three good cappuccinos of five chosen cappuccinos from all the twenty cappuccinos.
After presentating my teacher showed me that some results (the ones I was certain were correct) could not be right. Great!
He just asked me some other questions, mainly if I could show them my calculating method. Sometimes the other math teacher said I explained it well but it is wrong what I could change to make it right – I DO NOT KNOW IF I WOULD HAVE I WOULD HAD DONE IT THIS WAY STRAIGHT AWAY! He asked me how a graph with a negative gradient looks like, what I could have done OTHERWISE to proof that the graph on the picture fits the cup (insert a point – WHICH ONE THERE WAS NONE GIVEN, demands)… I am not very interested into getting to know the result.
I hope my explanation is not that difficult to understand, I cannot express my mathematical thoughts in German so English is even worse.