Question 5.
a) The 4h term of a G.P. is 16 and the 7th term is 128. Find the first term and common
ratio of the series.
[3]
hl Amante 0902
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Answered by
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Answer:
First term = 2, common ratio = 2.
Step-by-step explanation:
Let a be the first term and r be the common ratio
The formula for nth term of GP is Tₙ = arⁿ⁻¹
T₄ = ar³ = 16 ----------- [1]
T₇ = ar⁶ = 128 ------------ [2]
Divide [2] by [1]
ar⁶/ ar³ = 128/16
=> r³ = 8
=> r = 2.
substitute value of r in [1]
ar³ = 16
=> a = 16/8 = 2.
Thus
First term = 2, common ratio = 2.
series is 2, 4, 8,16,32.....
Answered by
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Answer:
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Step-by-step explanation:
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