Question

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
7.27​

Answer 1

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.....

Answer 2

Answer:

....

Step-by-step explanation: