Question

how can proveing that if a and b are natural numbers and p and k are primes so than for every a and b there are always one p and k such that a=(p-1)/2 and b=(k-1)/2 ?

Answer 1

tis not necessary
simplifyin ur eq we get
2a=p-1
hence this wud be true for all cases where p is both odd n prime to give
p-1=2a==even num
it be valid if a=3 then p=7 true
but if a=10 then p=21 not prime
a=4 then p=9 not true either

Answer 2

so 1=(3-1)/2
2=(5-1)/2
...
...
n=(2n+1-1)/2
n=2n/2
n=n

... so hope so much that you like it ,... yes ?

Answer 3

... so but how can be proven that is true ?

Answer 4

... so i think by math induction

Answer 5

yes ?

so if yes than ok but how please ?

Answer 6

it is NOT TRUE that every time p will be prime

Answer 7

thats what i m tryin to tell u
u cant prove smth thats not true

Answer 8

why ? if p and k are always primes grater or equal 3

Answer 9

look at my first reply

Answer 10

for a =10
we dont get p as a prime number

Answer 11

for a =4
we dont get p as a prime no

Answer 12

3=2*1+1 --- 1=(3-1)/2
5=2*2+1 --- 2=(5-1)/2
7=2*3+1 --- 3=(7-1)/2

11=2*5+1 --- 5=(11-1)/2
13=2*6+1 --- 6=(12-1)/2

17=2*8+1 --- 8=(17-1)/2
19=2*9+1 --- 9=(19-1)/2

Answer 13

- ok
- so than if this not is possibill getting for every natural numbers than from this result that for every natural numbers not exist one prim number for what we can writing that
a=(p-1)/2 --- yes ?

- so but we know that every primes can be writing in the form of 2n+1

- than ???