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No. of Prime Factors OR no. of Factors

Expert replies
by monusangeeta » Sat Jul 31, 2010 11:54 pm
Dear Experts,

Need your help, should 1 be the part of no. of factor calculation while solving a question, which asks to identify no. of factors for some value x.

Thanks in advance,

Regards,
monusangeeta
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Source: — Problem Solving |

by kvcpk » Sun Aug 01, 2010 1:26 am
monusangeeta wrote:Dear Experts,

Need your help, should 1 be the part of no. of factor calculation while solving a question, which asks to identify no. of factors for some value x.

Thanks in advance,

Regards,
monusangeeta
IMO Yes. 1 should be a part of number of factors.

For example, 2 has 2 factors. (1 and 2)

Let me share a simple trick for finding number of factors.
Let us find Number of factors for 36
36 = 2^2 * 3^2 [Convert into product of prime powers]
Number of factors = (Power of first prime +1)(Power of Second Prime +1)...
Hence number of factors = (2+1)(2+1) = 3*3 = 9
Let us check this:
Factors of 36 =
1,2,3,4,6,9,12,18,36
Hence 9 factors.

Hope this helps!!
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