Plz answer this qstn.
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nth term of a GP is given by ar^(n-1), where a is the first term , r is the common ratio
4th term: ar³ = 10
7th term: ar^6 = 80
divide the two equations: r³= 8
hence r is 2.
a(2)³ = 10, hence a is 1.25
for the last term:
ar^(n-1) = 2560
therefore 2^(n-1)=2560/1.25= 256x8=2^11
hence n-1 is 11
n = 12
meaning there are 12 terms
4th term: ar³ = 10
7th term: ar^6 = 80
divide the two equations: r³= 8
hence r is 2.
a(2)³ = 10, hence a is 1.25
for the last term:
ar^(n-1) = 2560
therefore 2^(n-1)=2560/1.25= 256x8=2^11
hence n-1 is 11
n = 12
meaning there are 12 terms
Sephy:
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