Sunday, 19 March 2023

GEOM. PROGRESSION G1

 The 1st term of a geometric progression is 7 and the 5th term is 112. Find i)the common ratio. ii) 10th term

 

Solution

 

G1=7, G5=112, n=5

 

i) Gn = G1rn-1;

 

G5 = G1r5-1;

 

G5 = G1r4;

 

112 = 7 x r4;

 

112 = 7r4;

 7       7

 

16 = r4;  Finding the fourth root of 16,

 

r = 2

 

 

 

Hence the common ratio is 2.

 

ii)  10th term

 

Gn = G1rn-1;

 

G10 = G1r10-1;

 

G10 = G1r9;

 

G10 = 7 x 29;

 

G10 = 7 x 512;

 

G10 = 3584

 

Hence the eighth term is 3584

 

TRY THIS………………………….. 

 

The 1st term of a geometric progression is 2 and the 6th term is 486. Find i) the common ratio. ii) 11th term.

 

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