Question

a=1-√5/2
a) a la patrat-a-1
b) (3a la patrat-3a-4) la 2021

Answer 1

Răspuns:

a)  0

b)  -1

Explicație pas cu pas:

a = (1-√5)/2

a²-a-1 = ?

a² = (1-2√5+5)/4 = (6-2√5)/4 = (3-√5)/2

a²-a-1 = (3-√5)/2 - (1-√5)/2 -²⁾1 =

= (3-√5-1+√5-2)/2 = 0

-----------------------------------

(3a²-3a-4)²⁰²¹ = ?

3a² = (9-3√5)/2

3a = (3-3√5)/2

3a²-3a-4 = (9-3√5-3+3√5-8)/2 = (-2/2) = -1

(3a²-3a-4)²⁰²¹ = (-1)²⁰²¹ = -1