Question

8.
Find all primes of the form n - 1 for natural number 'n'.
(a) Find number of divisors of 210 x 315 x 1513
(b) Number of distinct prime factors of 210 × 315 x 1513
11 and 13 respectively such​

Answer 1

Answer:

a)In number theory, the number of distinct prime factors of an integer n is denoted by ω(n). Also,  

ω(mn)=ω(m)+ω(n) and for any positive integers n and x, ω(n  x  )=ω(n)

Now,

ω(2  10

×3  15  ×15  13  )

=ω(2  10  ×3  15  ×3  13  ×5  13  )

=ω(2  10  ×3  28  ×5  13  )

=ω(2  10  )+ω(3  28  )+ω(5  13  )

=ω(2)+ω(3)+ω(5)

=1+1+1

=3

Answer 2

Answer:

above answer is right .