Consider the following statements I : The number of non-trivial even divisors of the number \(2^{\alpha_1}…

Consider the following statements I : The number of non-trivial even divisors of the number \(2^{\alpha_1} 3^{\alpha_2} 4^{\alpha_3} 5^{\alpha_4} 6^{\alpha_5}\), is \(\left(\alpha_1+1\right)\left(\alpha_2+1\right)\left(\alpha_3+1\right)\left(\alpha_4+1\right)\left(\alpha_5+1\right)-2\) II : The number of non-trivial odd divisors of the number \(2^{\alpha_1} \cdot 3^{\alpha_2} \cdot 4^{\alpha_3} \cdot 5^{\alpha_4} \cdot 6^{\alpha_5}\), is \(\alpha_2+\alpha_4+\alpha_5+\alpha_2 \alpha_4+\alpha_4 \alpha_5\). Then
  1. I is false and II is false
  2. I is true and II is true
  3. I is false and II is true
  4. I is true and II is false

Solution

Given number \(=2^{\alpha_1} 3^{\alpha_2} 4^{\alpha_3} 5^{\alpha_4} 6^{\alpha_5}\) \(=2^{\alpha_1+2 \alpha_3+\alpha_5 3^{\alpha_2}+\alpha_5 5^{\alpha_4}}\) Number of non-trivial even divisors \(=\left(\alpha_1+2 \alpha_3+\alpha_5\right)\left(\alpha_2+\alpha_5+1\right)\left(\alpha_4+1\right)-1\) And, number of non-trivial odd divisors \(\begin{aligned} & =\left(\alpha_2+\alpha_5+1\right)\left(\alpha_4+1\right)-1 \\ & =\alpha_2+\alpha_4+\alpha_5+\alpha_2 \alpha_4+\alpha_4 \alpha_5+1-1 \end{aligned}\) \(\therefore\) Statement \(\mathrm{I}\) is false and \(\mathrm{II}\) is true.

Asked in: AP EAMCET 2019 (22 Apr Shift 1)

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