Question

Cm a^4-3a^3+6a^2-5a+3>0

Answer 1

tui ko biet

Answer 2

\(a^4-3a^3+6a^2-5a+3=\left(a^2-2a+3\right)\left(a^2-a+1\right)\)

có \(a^2-2a+3=\left(a-1\right)^2+2>0,a^2-a+1=\left(a-\frac{1}{2}\right)^2+\frac{3}{4}>0\)

suy ra đpcm.