Question

Biểu thức vi-ét

x1^2- x2^2=

x1^3- x2^3=

x1^4- x2^4=

x1/x2+ x2/x1=

Giúp mình với

Answer 1

\(x_1^2-x_2^2=\left(x_1-x_2\right)\left(x_1+x_2\right)\)

\(=\pm\sqrt{\left(x_1+x_2\right)^2-4x_1x_2}\cdot\left(x_1+x_2\right)\)

\(x_1^3-x_2^3\)

\(=\left(x_1-x_2\right)^3+3x_1x_2\left(x_1-x_2\right)\)

\(=\pm\left[\left(x_1+x_2\right)^2-4x_1x_2\right]^3+3\cdot x_1x_2\cdot\pm\left(\left(x_1+x_2\right)^2-4x_1x_2\right)\)