dados
a1=81
an=16
n=5
hallar
r=?
sn=?
Akenaton:
Es progresion aritmetica o geometrica??
progresion geometrica
Respuestas
Respuesta dada por:
2
an = a1*[r^(n-1)]
a1 = 81; a5 = 16; n = 5
16 = 81*[r^(5-1)]
16 = 81*[r^4]
r^4 = 16/81
16 = 2^4
81 = 3^4
r^4 = (2^4/3^4)
![r =\sqrt[4]{ \frac{2^{4}}{3^{4}}} =2/3](https://tex.z-dn.net/?f=r+%3D%5Csqrt%5B4%5D%7B+%5Cfrac%7B2%5E%7B4%7D%7D%7B3%5E%7B4%7D%7D%7D+%3D2%2F3 "r =\sqrt[4]{ \frac{2^{4}}{3^{4}}} =2/3")
r = 2/3
Sn = [(an*r - a1)/(r - 1)]
Sn = S5
S5 = [(16*(2/3) - 81)/((2/3) - 1)]
S5 = [(32/3 - 81)/(-1/3)]
S5 = [(-211/3)/(-1/3)] = 211
S5 = 211
Rta: r = 2/3; S5 = 211
a1 = 81; a5 = 16; n = 5
16 = 81*[r^(5-1)]
16 = 81*[r^4]
r^4 = 16/81
16 = 2^4
81 = 3^4
r^4 = (2^4/3^4)
r = 2/3
Sn = [(an*r - a1)/(r - 1)]
Sn = S5
S5 = [(16*(2/3) - 81)/((2/3) - 1)]
S5 = [(32/3 - 81)/(-1/3)]
S5 = [(-211/3)/(-1/3)] = 211
S5 = 211
Rta: r = 2/3; S5 = 211
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