I received an email today from a friend with some amusing math-not-so-correct examples as attached images. You may have seen them but I thought that this one was good by a student named Peter.
Very amusing :)
This takes me back to my teens and some math that I did at school. We were doing vectors and were told by our missing-link math teacher that if we didn't underline the letter in the equation then it wasn't a vector but a variable and there'd be big trouble. We took him seriously because he usually hit us around the head if we didn't listen. Although I was an A-student at math I didn't respect the feeble and simple minded teachers we had teaching us and so was somewhat of a rebel and a favorite target for teachers.
Our close-descendant-of-cave-man math teacher had set us some exercises to do and was cruising up and down the aisles of the silent classroom looking over our shoulders. I felt a whack on the back of the head and my nose hit the desk. When the stars stopped spinning I could see Hall thudding his index finger on my paper.
Hall: "You forgot to underline a vector Ellis."
Me: "That's not a vector sir, that's a variable."
Hall stopped tapping his finger and moved on without saying anything more. About 10 minutes later he was doing an example on the blackboard and I noticed that he hadn't underlined one of the vectors.
"Sir," I shouted out, "you haven't underlined vector k in the second row."
Hall took a couple of steps back from the board and took a look at what he was writing and then went back and underlined the vector that he'd missed earlier.
Dave Baker, who shared a desk with me, piped up: "Sir, can Ellis hit you on head?"
There was a small amount of laughter which quickly stopped when Hall turned around.
"Watch it Baker," Hall said, "or you'll find yourself exiting the room face first."
And that is how we studied math in the early 80's at one of the most expensive schools in South Africa.
Later on that term we were set mid year exams. There were about 100 of us in my year and we all had to do math. The first question in the exam involved vectors and whoever had set the exam forgot to underline one of the variables in the question. I knew how to solve the question and what they wanted but I just wrote "solution not possible because of a mix of variables and vectors" - or something like that. One other person (Raymond McLucky) did the same as me but the other 98 elected to spend the 10 minutes required to answer the question. It didn't really bother that I might score 0 for the question because I knew I'd get the rest of the paper right and still get an A which is a rare luxury that a student might have; That is to test the resilience of the examiners to face up to their errors.
Our teachers were the last people that would ever admit that they were wrong and so it came as a shock that I was given full marks for that question. I was warned that I'd sailed extremely close to the wind and not to do it again - advice which I immediately ignored because of where it came from.