Question

6.-Calcula x en 0,2 + 0,4 + 0,6 + … + x = 11

Answer 1

A₀ = 1/5

r = 1/5

An = rn+A₀

An = x

x = (1/5)(n-1) + 1/5

n = (x-1/5)/(1/5) + 1 = 5x

Sn = n(A₀+An)/2

11 = n(1/5+An)/2

22 = 5x(1/5+x)

22 = 5x² - x

0 = 5x²+x-22

x₁ = 2 ✅

x₂ = -2,2 ✖

x = 2