\(\dfrac{75^{50}.2^{100}}{100^{50}.9^{25}}=\dfrac{\left(25.3\right)^{50}.2^{100}}{\left(25.4\right)^{50}.\left(3^2\right)^{25}}=\dfrac{25^{50}.3^{50}.2^{100}}{25^{50}.4^{50}.3^{50}}=\dfrac{25^{50}.3^{50}.2^{100}}{25^{50}.\left(2^{2^{ }}\right)^{50}.3^{50}}=\dfrac{25^{50}.3^{50}.2^{100}}{25^{50}.2^{100}.3^{50}}=1\)

\(\dfrac{75^{50}\cdot2^{100}}{100^{50}\cdot9^{25}}=\dfrac{25^{50}\cdot3^{50}\cdot4^{50}}{25^{50}\cdot4^{50}\cdot3^{50}}=1\)

\(\dfrac{75^{50}.2^{100}}{100^{50}.9^{25}}=\dfrac{\left(25.3\right)^{50}.2^{100}}{\left(25.4\right)^{50}.\left(3^2\right)^{25}}=\dfrac{25^{50}.3^{50}.2^{100}}{\left(25^{50}\right).\left(2^2\right)^{50}.\left(3^2\right)^{25}}=\dfrac{25^{50}.3^{50}.2^{100}}{25^{50}.2^{100}.3^{50}}=1\)

\(\dfrac{75^{50}.2^{100}}{100^{50}.9^{25}}\)

\(=\dfrac{\left(3.5^2\right)^{50}.\left(2^2\right)^{50}}{\left(2^2.5^2\right)+\left(3^2\right)^{50}}\)

\(=\dfrac{ \left(3.25\right)^{50}.4^{50}}{\left(4.25\right)^{50}.3^{50}}\)

\(=\dfrac{3^{50}.25^{50}.4^{50}}{4^{50}.25^{50}.3^{50}}=1\)

Đáp án D

Các quần thể đang ở trạng thái cân bằng di truyền là: (1),(2),(4)

Chọn đáp án D

Các quần thể đang ở trạng thái cân bằng di truyền là: (1), (2), (4).

\(B=50+\frac{50}{3}+\frac{25}{3}+\frac{20}{4}+\frac{10}{3}+\frac{100}{6.7}+...+\frac{100}{98.99}+\frac{1}{99}\)

\(B=\frac{100}{1.2}+\frac{100}{2.3}+\frac{100}{3.4}+\frac{100}{4.5}+\frac{100}{5.6}+\frac{100}{6.7}+...+\frac{100}{98.99}+\frac{100}{99.100}\)

\(B=100\left(\frac{1}{1.2}+\frac{1}{2.3}+\frac{1}{3.4}+\frac{1}{4.5}+\frac{1}{5.6}+\frac{1}{6.7}+...+\frac{1}{98.99}+\frac{1}{99.100}\right)\)

\(B=100\left(1-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+\frac{1}{3}+...+\frac{1}{98}-\frac{1}{99}+\frac{1}{99}-\frac{1}{100}\right)\)

\(B=100\left(1-\frac{1}{100}\right)\)

\(B=100.\frac{99}{100}=99\)

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