Proof of Angles: Does it Seem Correct?

  • Thread starter Thread starter chemistry1
  • Start date Start date
  • Tags Tags
    Angles Proof
AI Thread Summary
The discussion focuses on a mathematical proof relating degrees and grads, starting with the conversion of 1 degree to 10/9 grads. The user generalizes this to x degrees equating to (10/9)x grads. The proof involves calculating the number of minutes in both degrees and grads, leading to a simplified fraction of 27/50. Feedback suggests avoiding mixed numbers for easier calculations, and an alternative simplification method is proposed. The proof appears to be validated by the participants in the discussion.
chemistry1
Messages
108
Reaction score
0
http://postimg.org/image/3mmlbro1p/
Hi, I just want to know if my proof seems ok.

So we can begin with :

1 degrees = 1+1/9 grads

we multiply by x to generalize

x degrees= x+x/9 grads

now, we take x degrees and multiply it by 60 minutes to know how many minutes it makes.We also do the same with x+x/9 grads but we multiply it by a 100 minutes. After, we put this form :

60x degrees/(100x+100x/9) grads

we simplify it :

60x/(1000x/9)grads

60x * 9/1000x

We cancel and simplify

3*9/50

Which finally gives us 27/50 for any 'x'.

Does this seem correct ? Thank you !
 
Last edited by a moderator:
Physics news on Phys.org
That seems to work. You can simplify the process by a few steps by doing

##\displaystyle\frac{60(x-\frac{x}{10})}{100(x)}## instead.
 
chemistry1 said:
http://postimg.org/image/3mmlbro1p/
Hi, I just want to know if my proof seems ok.

So we can begin with :

1 degrees = 1+1/9 grads
It's a bad idea to use mixed numbers like 1 + 1/9, because it makes the calculations more difficult.

1 deg. = 10/9 grads
chemistry1 said:
we multiply by x to generalize

x degrees= x+x/9 grads
x deg. = (10/9)x grads
chemistry1 said:
now, we take x degrees and multiply it by 60 minutes to know how many minutes it makes.We also do the same with x+x/9 grads but we multiply it by a 100 minutes. After, we put this form :

60x degrees/(100x+100x/9) grads


we simplify it :

60x/(1000x/9)grads

60x * 9/1000x

We cancel and simplify

3*9/50

Which finally gives us 27/50 for any 'x'.

Does this seem correct ? Thank you !
 
Last edited by a moderator:
Ok, thanks for the info !
 
I tried to combine those 2 formulas but it didn't work. I tried using another case where there are 2 red balls and 2 blue balls only so when combining the formula I got ##\frac{(4-1)!}{2!2!}=\frac{3}{2}## which does not make sense. Is there any formula to calculate cyclic permutation of identical objects or I have to do it by listing all the possibilities? Thanks
Essentially I just have this problem that I'm stuck on, on a sheet about complex numbers: Show that, for ##|r|<1,## $$1+r\cos(x)+r^2\cos(2x)+r^3\cos(3x)...=\frac{1-r\cos(x)}{1-2r\cos(x)+r^2}$$ My first thought was to express it as a geometric series, where the real part of the sum of the series would be the series you see above: $$1+re^{ix}+r^2e^{2ix}+r^3e^{3ix}...$$ The sum of this series is just: $$\frac{(re^{ix})^n-1}{re^{ix} - 1}$$ I'm having some trouble trying to figure out what to...
Back
Top