Answer:
110.01 (aprox)
Explanation:
x + (1/x) = 5
x(x + (1/x)) = x(5)
x*x + x*1/x = 5x
x² + 1 = 5x
x² - 5x + 1 = 0
x = {-(-5)±√((-5²) -(4*1*1))} / (2*1)
x = {5±√(25-4)} / 2
x = {5±√21} / 2
x = {5±4.5826} / 2
x₁ = {5-4.5826} / 2 = 0.4174/2 = 0.2087
x₂ = {5+4.5826) / 2 = 9.5826/2 = 4.7913
Comprobación:
x₁
0.2087 + 1/0.2087 = 5
0.2087 + 4.7913 = 5
x₂
4.7913 + 1/4.7913 = 5
4.7913 + 0.2087 = 5
Respuesta:
x₁
(0.2087)³ + 1/(0.2087)³ = 0.0091 + 1/0.0091 = 0.0091 + 110.0101 = 110.019
x₂
(4.7913)³ + 1(4.7913)³ = 110 + 1/110 = 110 + 0.01 = 110.01