Answer:
S infinity= -51/4
Step-by-step explanation:
First term
ar= -9
Fifth term
ar⁴= 1/3
Solving for the value of the r and a
ar= -9
ar⁴= 1/3
Dividing each other
r³=1/3 * -1/9
r³=-1/27
r= 3√-1/27
r= -1/3
Solving for a
ar= -9
a(-1/3)= 9
a= 9*-3
a= -27
Sum of a go to infinity is given by the formula
S infinity= a/(1-r)
S infinity= -27/(1-(-1/3))
S infinity= -27/(1+1/3)
S infinity= -27 * 3/4
S infinity= -51/4
