# Why did my teacher give points off for saying the tangent of 180 and 360 degrees = 0?

1. Mar 20, 2012

### e^(i Pi)+1=0

????
1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution

2. Mar 20, 2012

Re: Why did my teacher give points off for saying the tangent of 180 and 360 degrees

Why do you think your teacher gave "points off"?

3. Mar 20, 2012

### Mentallic

Re: Why did my teacher give points off for saying the tangent of 180 and 360 degrees

You need to be more specific. What was the question?

Maybe you were restricted to the values of $-\pi/2$ to $\pi/2$ for example.

4. Mar 20, 2012

### e^(i Pi)+1=0

Re: Why did my teacher give points off for saying the tangent of 180 and 360 degrees

I guess I should have given more information. It was a no-calculator test. The part I'm talking about you had to fill in the famous unit circle chart.

5. Mar 20, 2012

### HallsofIvy

Staff Emeritus
Re: Why did my teacher give points off for saying the tangent of 180 and 360 degrees

Then perhaps you were expected to say $tan(\pi)= tan(2\pi)= 0$ rather than using degrees.

6. Mar 20, 2012

### e^(i Pi)+1=0

Re: Why did my teacher give points off for saying the tangent of 180 and 360 degrees

7. Mar 20, 2012

### Staff: Mentor

Re: Why did my teacher give points off for saying the tangent of 180 and 360 degrees

Your instructor probably dinged you for writing ∅ (empty set) instead of 0. He or she might have been confused because you write ∅ in some places and 0 in others, without consistency.

8. Mar 20, 2012

### HallsofIvy

Staff Emeritus
Re: Why did my teacher give points off for saying the tangent of 180 and 360 degrees

However, he/she did not take points off for that same answer for $\theta= 0$. I'm confused!

9. Mar 20, 2012

Re: Why did my teacher give points off for saying the tangent of 180 and 360 degrees

Could be speed marking and the teacher overlooked it.Having had another look it seems as if he/she deducted four marks(-1 and -3)

Last edited: Mar 20, 2012
10. Mar 20, 2012

### e^(i Pi)+1=0

Re: Why did my teacher give points off for saying the tangent of 180 and 360 degrees

No, it was only -1. There was also a -2 higher up on the page.

11. Mar 20, 2012

### Mentallic

Re: Why did my teacher give points off for saying the tangent of 180 and 360 degrees

Why don't you ask her why she removed the marks?

12. Mar 20, 2012

### e^(i Pi)+1=0

Re: Why did my teacher give points off for saying the tangent of 180 and 360 degrees

Oh I plan to...

13. Mar 20, 2012

### jey1234

Re: Why did my teacher give points off for saying the tangent of 180 and 360 degrees

I'm pretty sure it's what Mark44 said and she probably won't change her mind but it's always worth asking

14. Mar 21, 2012

### Mentallic

Re: Why did my teacher give points off for saying the tangent of 180 and 360 degrees

I doubt that's the case, because for one, she wasn't consistent in dragging down marks for each time he wrote the empty set, also, it's sometimes common practice to write zero with the slanted line through it to denote that it is in fact zero as opposed to the letter O. And finally, if he's answering simple trig questions, I doubt they've learnt about sets yet.

15. Mar 22, 2012

### Staff: Mentor

Re: Why did my teacher give points off for saying the tangent of 180 and 360 degrees

I think I, too, would have deducted marks, as it appears you changed a 1 to a 0, or a 0 to a 1, and it's not clear what your final answer is supposed to be. Or else you are hedging your bets and hoping to be given the benefit of the doubt whatever the correct answer may be. :tongue:

16. Mar 22, 2012

### e^(i Pi)+1=0

Re: Why did my teacher give points off for saying the tangent of 180 and 360 degrees

What are you talking about? Where did I change a one to a zero?

17. Mar 22, 2012

### Staff: Mentor

Re: Why did my teacher give points off for saying the tangent of 180 and 360 degrees

You crossed zero can be interpreted as you changed 1 to 0 (or vice versa). Doesn't mean you did, but it is not necessarily obvious you didn't.

18. Mar 22, 2012

### Ray Vickson

Re: Why did my teacher give points off for saying the tangent of 180 and 360 degrees

Nobody said you did; they just said it looked like you might have, and that is probably why marks were taken off. (A 0 with a line through it *might* be interpreted as a zero crossed out, rather than a zero.)

RGV

19. Mar 23, 2012

### micromass

Staff Emeritus
Re: Why did my teacher give points off for saying the tangent of 180 and 360 degrees

Why did you write 0 in some place and $\emptyset$ in other places??

20. Mar 23, 2012

### e^(i Pi)+1=0

Re: Why did my teacher give points off for saying the tangent of 180 and 360 degrees

No reason. I always put a slash through my zeros but just forgot here for some reason.