Math problem

[kingW3]

Had similar problem on exam,took me a while to solve can you do it?
Solve for n where n is natural number

[courierpower]

multiply first term with 1 but as "(/2-1)/2-1)" (lazy do download mathtype program i mean root 2 with /2), it will be /2-1 at end. Do the same calculation for each part. It will be like (/2-1) + (/3-/2) + (/4-/3) and u will see the rooted numbers remove each other, only -1 and the last term remains (/n+1) so, (/(n+1))-1=15, /(n+1)=16 n+1=256 n=255

[donjacrtasamir]

Had similar problem on exam,took me a while to solve can you do it?
Solve for n where n is natural number

lol people here get confused when they have to multiply 2 numbers and you think they can solve this....

[kingW3]

Wanted to see who can solve this,courier solved it though.Nice job

[div.ide]

Oh, I'm late.

By the way, fuck you, you made me spend 90 minutes trying to remember that little trick. I feel stupid. Especially because I did very similar exercise several yeras ago.

[courierpower]

in these kind of problems, i mean root number + or - sth else below the divide line, we multiply with their

Spoiler for Hiden:

eşlenik ifade

neutralizer or whatever you call i dont know math words in english so well,
for any term like"/x+/y" you just multiply that with "/x-/y" and it becomes "x-y" and you get rid of roots below the divide line. I could do these since 3 years ago when i was 8. grade. We do learn much stuff about math.

[kingW3]

You rationalize,anyway this was in a test for mathematics high school(hardest) + these kind of questions are also in exams for faculty(college),i think you can solve it with Stolz theorem but not sure.
Btw if you're in the mood i'll continue,a easier one
120!
------
12¹²⁰

Simplify it

[courierpower]

wasnt that "120!" factorial? or !120 is sth different?

[kingW3]

Oops,mistype it's factorial

[courierpower]

Well all i found is that 2².3⁶² remains at the bottom dunno about top this wasn't easier 

[div.ide]

So stupid.

5²⁸ * 7¹⁹ * 11¹⁰ * 13⁹ * 17⁷ * 19⁵ * 23⁵ * 29⁵ * 31³ * 37³ * 41² * ... * 59² * 61 * ... * 113
2¹²⁴*3⁸⁹

Note - all power bases in above fraction are prime.

TBH it doesn't look any simpler

[kingW3]

I guess that's the answer since my friend(who told me that question just said it is something/2^124*3^89(at least i think),although i think it can be even shorter but meh
How much are there double-digit natural numbers where the result of addition of the digits doesn't change if we multiply it by:2,3,4,5,6,7,8,9
(for example
23=2+3; 23*2=46=4+6 which isn't the number we're looking for clearly)

A)0; B)1; C)2; D)3; E)4;

[Nistor]

just tell me why do i need this shit in my life?
i finished school for some water shit... and need to know this common... xD

[div.ide]

It can't be simpler, because, as I said, I left only prime numbers Some powers might be off though. I'm almost sure there are a few.
Let's say we have a double digit number xy, x and y being digits. Let's also call n any of {2,3,4,5,6,7,8,9}. If xy solves our problem, it woud be true that

10x + y = n*10*x + n*y
that gives us

10*(n-1)*x = -(n-1)*y // :10*(n-1)
x = -y/10

only natural number that solves this equation would be
x=0
y=0
but that doesn't make double-digit number. Therefore there's no such numbers.

Note that

23=2+3; 23*2=46=4+6 which isn't the number we're looking for clearly)

bolded parts are complete bullshit 23!=5 and 46!=10
King, calcuate this (only pen, paper and your brain allowed - no calculators etc.):

423 134 * 846 267 - 423 133
----------------------------------------- = ?
423 133 * 846 267 - 423 134

[BLOODYALBOZ]

1.
Upper numbers are equal to lower ones (idk how is said in english) and when you divide a number with himself it will always give 1 (4/4=1)