\(\Leftrightarrow\left(x-\frac{1}{2}\right)^2\left(2x-10\right)^{10}=C^k_2x^{2-k}\left(-\frac{1}{2}\right)^k\cdot C^i_{10}\left(2x\right)^{10-i}\left(-10\right)^i=C^k_2C^i_{10}\left(-\frac{1}{2}\right)^k\left(-10\right)^i\cdot2^{10-i}\cdot x^{12-k-i}\)
k | 0 | 1 | 2 |
i | 4 | 3 | 2 |
12-k-i=8 |
số hạng : \(C^0_2C^4_{10}\cdot10^4\cdot2^6+C^1_2C^3_{10}\cdot\left(-\frac{1}{2}\right)\cdot\left(-10\right)^3\cdot2^7+C^2_2C^2_{10}\cdot\frac{1}{2}^2\cdot10^2\cdot2^8\)