Question

Determine a razão das progressões geométricas dadas por: a15= -2 e a18= 1/4

Answer 1

a15=-2
a18=1/4

a15=a1×q^14. -2=a1×q^14
=>
a18=a1×q^17. 1/4=a1×q^17

a1=-2/q^14. ..……...............
=>
1/4=-2/q^14×q^17. 1/4=-2q^17-14

…......... ..........
=>. =>
1/4=-2×q^3. q^3=1/4÷(-2)

........ ...........
=>. =>
q=3√1/4×(-1/2) q=3√-1/8.

q=-1/3