Question

Qual o valor minimo da função : f(x)=5x²-8x+2?

Answer 1

Δ = b2 - 4.a.c
Δ = -82 - 4 . 5 . 2
Δ = 64 - 4. 5 . 2
Δ = 24

Há 2 raízes reais.

x = (-b +- √Δ)/2a

x' = (--8 + √24)/2.5

x' = 12,898979485566356 / 10

x' = 1,2898979485566355

x'' = (--8 - √24)/2.5

 x'' = 3,1010205144336442 / 10

x'' = 0,31010205144336445

Answer 2

Xv= -b /2*a         a= 5  b= -8  c= 2

Xy= Δ/4*2                    

Δ=b²-4*5*2

Δ=(-8)²-4*5*2

Δ=64-40

Δ=24

Xv= -8/2*5 Xv -8/10 = 0,8

Xy= -24/20   Xy  =  -1,2

R= -1,2