Question:

Lat "a" be a positive numbere which is greater than 1 , say N=a^pb^qr^swherw a,b,c are diffrent primes and ?

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the number of ways in which N can be resolved is

N=1\2 (p+) (q+1) (s+1)

can any one explain it very clearly ,in few sentences ,

be swift!!!!

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  1. If I can clarify, this appears to be the problem, where, if

    n = a^p * b^q * c^r (being the prime factorisation of n),

    where a, b, c are different primes and p, q, r are integers

    (not necessarily different), then the number of distinct

    divisors of n is given by the number-theoretic function

    T(n) = (p + 1)(q + 1)(r + 1).

    To see how simply this works, let a = 2, b = 3, c = 5

    and let p = 2, q = 2, r = 2.

    Thus, N = 2^2 * 3^2 * 5^2 = 2 * 2 * 3 * 3 * 5 * 5

    Now all we have to do is find all the different combinations

    of factors, 1 at a time, 2 at a time, etc., up to 6 at a time.

    Here they are, all 27 of them, i.e. (2 + 1)(2 + 1)(2 + 1).

    1 : 1 (1 divides into all integers)

    2 : 2

    3 : 3

    5 : 5

    4 : 2 * 2

    6 : 2 * 3

    10: 2 * 5

    9 : 3 * 3

    15: 3 * 5

    25: 5 * 5

    12 : 2 * 2 * 3

    20 : 2 * 2 * 5

    18 : 2 * 3 * 3

    30 : 2 * 3 * 5

    50 : 2 * 5 * 5

    45 : 3 * 3 * 5

    75 : 3 * 5 * 5

    36 : 2 * 2 * 3 * 3

    60 : 2 * 2 * 3 * 5

    100: 2 * 2 * 5 * 5

    90 : 2 * 3 * 3 * 5

    150: 2 * 3 * 5 * 5

    225: 3 * 3 * 5 * 5

    180 : 2 * 2 * 3 * 3 * 5

    300 : 2 * 2 * 3 * 5 * 5

    450 : 2 * 3 * 3 * 5 * 5

    900 : 2 * 2 * 3 * 3 * 5 * 5

    So, each factor is of the form a^x * b^y * c^z,

    where x ≤ p, y ≤ q and z ≤ r.

    Because p = 2, then x can only be 0, 1 or 2 ( 3 values).

    Likewise, y and z can also only be one of these 3 values.

    So with n = a^p * b^q * c^r, a^p could be 2^0, 2^1 or 2^2,

    b^q could be 3^0, 3^1 or 3^2 and c^r could be 5^0, 5^1 or 5^2.

    3 ways for first position times 3 ways for second position

    times 3 ways for third position = 27 combinations.

    The number of ways for each integer p, q, r is thus p+1,

    q+1 and r+1, the "+1" being for the prime raised to zero,

    in addition to the actual values of p, q and r.

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